Optical fiber Cascaded FabryPerot Interferometers (CFPIs) sensors based on vernier effect were manufactured by splicing a segment of Hollow Core Fiber (HCF) between two segments of Single Mode Fiber (SMF), and its temperature characteristics were investigated theoretically and experimentally. Simulation and experimental results verify the phenomenon exists in CFPIs sensors, the interference spectra of some sensors based on vernier effect shift to longer wavelength while others shift to shorter wavelength when temperature increases. The phenomenon can be interpreted well based on the value D, which is defined as the Free Spectrum Range (FSR) difference of the cascaded FPIs. Under the condition that temperature increases, the positive or negative of D determines that the spectrum shifts towards longer wavelength or shorter wavelength. Besides, the investigation shows that D makes a great influence on temperature sensitivity. The temperature sensitivity improves with D decreasing. The temperature sensitivities of our experimental sensors are 163.8 pm/℃ and －75 pm/℃, which corresponding D are 0.055 nm and －0.456 nm, respectively. By optimizing the length of the HCF and the caudal SMF proportionally, a simple, compact, lowcost and highsensitivity CFPIs temperature sensor would be achieved.