A novel power generator in the tire which is applied in a wireless Tire Pressure Monitor System(TPMS) was designed. The piezoelectric convertor constructed by bender arrays was merged to the inner surface of a tire to transform the mechanical deformation into the electric power and supply to the sensors of TPMS. A Finite Element Model(FEM) for the convertor was established based on the second piezoelectric function and the piezoelectric convertor with different sizes was analyzed by ANSYS 11.0 in a transient method. Then,a target of 6 cm² was selected to observe its characteristics,and the effective current is 5 μA. As the wireless sending component needs 10 mA every 30 s,an array with 40 piezoelectric convertors was used in the generator and a power conditioning circuit with a multiple path charge coupling module was also designed. Experiments show that when the frequency of tire rotation is 15 Hz,the average power through the conditioning circuit is 150－350 μW and the instantaneous power can reach 50 mW,which proves that the power generator can work efficiently.