Underwater gun is a new kind of arm for underwater combat army.Temperature measurements of its chamber wall and comparing the temperature change launching in the air and underwater have an important meaning for the ballistic model parameters choosing.At the same time

the temperature distribution of chamber wall is helpful for studing chamber burning and prolonging bore life.In order to measure transient wall temperature changes of underwater gun in the launch process

PtRt10-Pt micro-thermocouple and test system are desinged.Wavelet analysis method is used to process test signals.Temperature variation rule of underwater gun in different fix up point is got for the study of the launch process of underwater gun firing and it is the foundation for other studies.