The shock wave free field pressure test is an important test method in the explosion test of weapons and ammunition. Currently, the commonly used pen sensor needs to be aligned with the detonation core, but it is difficult to achieve accurate alignment in dynamic explosion or complex explosion, which will cause large test errors. To solve the above problems, a spherical sensor structure for air explosion field testing is designed, The design effectively realizes the measurement of shock wave in multiple directions and overcomes the defect of the traditional sensor which is sensitive to the location of the detonation core. The sensor adopts piezoelectric ceramic as the sensitive element and adopts conical structure at one end of the connected sensor to improve its performance and stability in the complex explosion environment .and its performance is calibrated on the shock tube platform to complete the explosion verification test. The test results show that the sensor's rise time is 1.23ms, the sensitivity is 100.34pC/kPa, The sensor tested free field pressures in six directions, and the distribution deviation is within ±7.1%