In order to investigate the thermal erosion characteristics and variation law of triple base propellant， various kinds of gun propellants with different components content were prepared. The erosion characteristics were determined through simulated test in a semi-closed bomb. The analysis reveals the impact of energy component and plasticizer content on gun propellant explosion temperature， and the impact of explosion temperature on erosion characteristics. The results indicate that changes in the explosion temperature of gun propellant， attributed to variations in cyclotrimetheylenetrinitramine （RDX）， nitroguanidine （NQ） and dioctyl phthalate （DOP） content， significantly affect erosion characteristics. An increase of 1% in RDX content results in an increase in explosion temperature by 0.59% and an increase in erosion rate by 1.23%. Compared with the absence of RDX， the erosion rate of 2% RDX-containing propellant increase 23.38%. Notably， an increase of 1% in NQ content reduces the explosion temperature by 0.23% and the erosion rate by 0.56%. An increase of 1% in DOP content reduces the explosion temperature by 2.99% and the erosion rate by 7.01%. For the triple base propellants within the range of explosion temperature from 2600-3100 K， an exponential relationship between the rate of erosion mass and explosion temperature is established， and characteristic coefficients of RDX， NQ， DOP system is given respectively， which is 0.106， 0.101， 0.163.