Abstract: In this work, the creep properties of China Low Activation Martensitic (CLAM) steel TIG welding joint have been carried out in the temperature of 823K and with the applied stress from 180 to 260 MPa. The creep curve and creepmechanism with mathematic model is analyzed. The results show that the TIG welding joints exhibited the typical three-stage creep curves; the minimum creep rate increasedat a constant temperature, the rupture time decreases with the stress increasing. The stress exponent n obtained by creep equation was higher than the typical values of 3~7, and the activation energy Q was about 436 KJ/mol.K, which is also higher than the self diffusion energy of Fe(300 KJ/mol·K) indicating a dislocation creep deformation mechanism.