In order to obtain piezoelectric coefficient of d31 PVDF film, a new quasistatic stretching direct measurement method was uesd. The tester and measurement results were presented in this paper. The values of piezoelectric coefficient d31 of PVDF film were more exactly measured at the temperature from -20～+70 ℃ during the test. The experiment also showed that the quasistatic stretching method for measuring piezoelectric coefficient of film is reliable and simple and the measuring results were reasonable and accurate.