Aiming at the differences of DC and AC harmonic current characteristics between valve bridge arm reactor for VSC-HVDC system and conventional DC smoothing reactor, based on the Yunnan asynchronous interconnection project, this paper studies the necessity of additional AC temperature rise test for bridge arm reactor, recommends AC temperature rise test methods and compares temperature rise experiments. Results show that firstly, the methods of temperature rise design and test for bridge arm reactor should not simply follow those methods for conventional DC smoothing reactor based on DC current distribution characteristics; secondly, the bridge arm reactors for Yunnan asynchronous interconnection project meet the temperature rise limit value requirements in AC-DC combined current. The research can provide reference for type design and selection of reactors under AC-DC combined large current projects in future.