To reduce thermal damage caused by high temperature during radiofrequency tissue welding, a novel water-cooled radiofrequency tissue welding electrode was designed. COMSOL Multiphysics was used to simulate in vitro welding process of porcine small bowel. Welding temperature and effect on biological tissue were analyzed through welding and bursting pressure experiments. Results showed simulation with temperature threshold method could solve reversible water evaporation problem in the existing model. Maximum and average welding temperatures of water-cooled electrodes were 139.8 ℃ and 112.5 ℃, respectively, which were significantly controlled compared to typical metal electrodes under the same conditions. Tissue welded by water-cooled electrodes reached bursting pressure of 63.6±13.7 mmHg and welding requirement was satisfied. Temperature predicted by simulation model fit well with experimental results, and water-cooled electrodes demonstrated effectiveness in welding tissue and controlling welding temperature.