Measuring instant dynamic parameters at the time of perforating is very important for evaluating the process of perforating. It is a necessary technology to research and explore oil field. For getting the down-hole dynamic pressure data in the process of perforating, a pressure tester of oil well is developed. Storage testing technology is applied in the device to record the change of down-hole annulus pressure at the condition of perforating and fracturing at real time. Self-contained power supply of the testing system is used to power during the testing process. Volume and capacity of the battery is lower for the limited volume of the testing system. According to actual testing environment, low power design is performed to the oil down-hole testing system. The total power consumption calculation and actual testing results show that the requirements of testing methods of down-hole pressure are met and the effectiveness of low power consumption design is verified.