The ambient temperature sensing is essential in industry, agriculture, medicine, food processing and so on. Optical fiber sensors have been widely valued by scholars due to the advantages of simple fabrication, electromagnetic interference resistance, chemical corrosion resistance and easily distributed measurement. In recent years, Hollow Core Fiber (HCF) has been investigated in fiber temperature sensing due to its hollow structure. In addition, antiresonant Negative Curvature Hollow Core Fiber (NCHCF) as a special hollow photonic crystal fiber, greatly reduces transmission loss of HCF by virtue of its negative curvature structure and quite thin cladding tube wall thickness. Hence, the mechanism of Multimode Interference (MMI) and Anti-Resonant (AR) of NCHCF are significantly enhanced, so it has more potential in the field of sensing and has become the focus in optical fiber sensing. At present, the sensitivity of the NCHCF cascaded temperature sensor based on the MMI mechanism is low. And some simulations have indicated that the high temperature sensitivity based on AR mechanism can be obtained by filling temperature-sensitive liquid into the hollow core of NCHCF. In order to simplify the fabrication of devices and obtain high temperature sensing sensitivity, the temperature sensing characteristics of the unfilled cascaded device based on AR and MMI are both studied theoretically and experimentally in this paper. Firstly, Single-Mode Fiber (SMF), Graded Index Fiber (GIF) and NCHCF are fused to form the cascaded fiber sensing structure (SMF-GIF-NCHCF-GIF-SMF). And then, the temperature sensing principle of the cascaded sensor based on MMI and AR is analyzed and the formulas are deduced. As temperature increases, the tube wall thickness and the refractive index of cladding and will increase due to the thermal expansion and thermal-optical effect of fiber materials, while the refractive index of air will decrease. Therefore, the dips based on MMI and AR both show red shift with the increases of temperature. The temperature sensitivity based on AR resonant dip is calculated as 17.25 pm /℃, and the sensitivity only caused by the thermo-optic effect of the fiber cladding material is 15.50 pm/℃. It is concluded that the thermo-optic effect of the fiber cladding material should play a leading role in temperature sensing. Therefore, the confinement losses of the core fundamental mode at corresponding resonant wavelength vary with different temperatures are simulated, where only the thermo-optic effect of the fiber cladding material is considered. And the simulation result is 15.57 pm/℃, which is consistent with the theoretical calculation. Finally, the temperature sensing experimental setup is designed and built. The temperature sensor is placed in the temperature controller and the endpoints of the sensor are connected with Broadband Light Source (BBS) and Optical Spectrum Analyzer (OSA), respectively. As the transmission bandwidth between adjacent AR resonant dips of NCHCF is large, the range of monitoring wavelength of the OSA is set as 600~1 700 nm, and its resolution is 0.02 nm. Multiple experiments are performed for monitoring MMI and AR dips when the temperature increases from 20 to 80 ℃ at a step of 10 ℃. It is found that the wavelength of each dip shifts as a function of temperature, which is fitted with an error bar. And the experimental results show that the temperature sensitivity and Detection Limit (DL) based on the MMI mechanism are 7.70 pm/℃ and 2.60 ℃, respectively. As for AR based sensors, there are three resonant dips in the resonant region of the transmission spectrum, which correspond to the three AR modes supported by NCHCF. The temperature sensitivities of the three dips are 17.29 pm/℃, 17.38 pm/℃ and 17.22 pm/℃, respectively, which are consistent with the theoretical results. And the DL based on AR mechanism is 1.16 ℃. Compared with the above experimental results, the temperature sensor based on AR mechanism has higher sensitivity and more fine detection, and thus AR mechanism is more suitable for temperature sensing. The temperature sensing experiment of the cascaded device is mainly carried out in the temperature range of 20~80 ?℃. However, the relevant studies have shown that the detection temperature based on the quartz material sensor can be up to 1 100℃. Therefore, the proposed sensor can be used in a higher temperature environment theoretically. Meanwhile, it has the advantage of good stability and can be widely used in environmental temperature detection scenes. In addition, the comparative study of dual mechanisms carried out in this paper can provide the theoretical basis for multi-parameter sensing.