Abstract: After high proportion of distributed photovoltaics (PVs) connected to the medium-and-low voltage distribution network (DN), the unbalance between PVs' high generating and users' low load demands in midday will lead to the reverse power flow in DN, which will cause overvoltage problem. On the basis of analyzing the mechanism of overvoltage problems, this paper proposes a quota allocation method for reverse power at PV-connected points based on Power Transfer Distribution Factor (PTDF) and voltage sensitivity matrix. When the reverse power of PV access point is greater than the quota and overvoltage problem is occur, the Shapley method is used to calculate the responsibility of each PV access point for the overvoltage. Finally, a 33-node study is used to verify the effectiveness of the proposed overvoltage responsibility sharing method.