The fault current characteristics of photovoltaic in distribution network causes uncertainty of distance protection branch coefficient, resulting in protection devices refusing to operate or mal-operating. In order to solve this problem, this paper puts forward to proceed with adaptive branch coefficient calculation according to the positive and negative sequence current of the protection. Then, zone II setting of distance protection can be identified. Finally, one distribution network is simulated using the PSCAD/EMTDC. The single-phase grounding fault and two-phase short circuit results of simulation show the validity and convenience of the method.