Abstract: The sorption and desorption behavior of tritium on the surface of copper were studied. After the exposure in the mixed gas of 50% deuterium and 50% tritium ( 15 MPa mixed gas, 8 h and 27 MPa mixed gas, 6 h exposure at 503 K ), the tritium desorbed at room temperature and during heating up to 1 173 K and total sorbed tritium of the samples were measured. The results show that the total sorbed tritium is 31.89 MBq/cm², the desorbed tritium is 29.18 MBq/cm². The standard deviation of measurement is 6.49％. The tritium released from copper at room temperature and during heating is mostly in the form of HT. The ratio of the free tritium to the sorbed tritium is 3.64%. There are three peaks in the thermal-desorption spectra from copper, their desorption temperatures of the three peaks are 650, 750, and 1 200 K, respectively. 