In term of the cross-sensitivity problem of ambient temperature in the process, a double-parameter sensor based on Twin-Core Fibers (TCF) and Long Period Gratings (LPG) is proposed. The theoretical mode is established, and the stimulated analysis is performed. The simulation results show that the bending sensitivity of 0.205 nm/cm with the micro-bending range of 20~60 cm and the temperature sensitivity of 1.208 nm/℃ with the temperature range of 0~100 ℃ are achieved. Based on a spectrometer having a wavelength distinguishability of 0.1 nm, the sensor can reach a distinguishability of 0.2 cm for bending and 0.079 ℃ for temperature. This sensor has advantages of simple structure and high sensitivity, and can effectively eliminate interference of ambient temperature which is available for shape monitoring of buildings such as tracks and bridges.