The invention relates to a method for checking the liquid volume of a gun recuperator by using the last detection data. The principle of the method is that if the recuperator does not leak liquid andair, the temperature and air pressure checked at before and after two times meet a gas state equation, and if the test pressure and the calculated pressure are in little different, the liquid volume of the recuperator can be determined to be normal. According to the method, based on the temperature and the initial pressure detected last time, only the temperature and the initial pressure need to be detected this time, no manual recoil is needed, so that the condition that most liquid volume is normal can be eliminated, and the liquid volume inspection can be completed. At present, a recuperateonly has a very small probability of leakage, so the method can be used to complete the liquid volume inspection without manual recoil operation in most cases, thus the service workload is greatly reduced, and the method is applicable to gun support of troops.