A siting and sizing method for the distributed photovoltaic power station in distribution network considering reverse power flow constraints is proposed.This method employs sequential Monte-Carlo simulation to deal with time-sequence and randomness characteristics of load and photovoltaic power output.The minimum electric energy demand from the main grid is taken as the optimization objective.The constraints are freedom from reverse power flow in distribution line equipped with circuit breaker with no bus voltage exceeding limit.While increasing the penetration of distributed photovoltaic generation and decreasing carbon emission，the proposed model makes it possible to avoid high frequency occurrences of the reverse power flow on the branch equipped with circuit breaker in the most commonly used model that endangers safe operation of the existing distribution network.Finally，the biogeography-based optimization algorithm with good performance is employed to solve the new optimization model.An IEEE 33-bus system has verified the effectiveness of the proposed method.