Abstract: For the heat generation of battery by discharging, the measurement accuracy could affect the thermal control design and the work temperature of the battery in orbit directly. In this paper, the vacuum adiabatic measuremeat method is used to analyze the heat leak of the test system, and a revision model is developed. And the measurement errors of the heat generation from an analogue battery are studied, and the solutions to improve the measurement accuracy are proposed. The experimental results show that the measurement error is less than 6% when the power of the heat generation is between 2~25 W and the discharging time is longer than 1 h, and it decreases with the increase of the power. When the power is beyond 10 W, the error is less than 3%, which meets the engineering requirements. It is meaningless to measure a mini-watt battery, whose absolute value of power of heat generation is less than 0.5 W, since the measurement error will be relatively large yet.