In view of the problem that the high overload environment and narrow test space of small caliber gun may lead to the failure of the chip， the shedding and fracture of the wire and solder joints of the projectile bottom pressure test system， the anti-high-overload research of the projectile bottom pressure test system was performed. The chip failure and isolation buffer mechanism model of the tester was established. The anti-high-overload performance of different mounting directions of the chip and different buffer materials were studied. The relationship between the chip's anti-overload capability and the installation direction， and the difference in the anti-overload performance of different buffer materials were obtained. The epoxy resin vacuum sealing method was proposed to solve the problem of shedding and fracture of wire and solder joint in high overload environment. Finally， the survivability and reliability of the projectile bottom pressure test system were verified by live ammunition test. The research results are of great significance to the design of the projectile bottom pressure test system for small caliber gun.