The current demand is to effectively reduce the power flow calculation of distribution network and to ensure the convergence accuracy in global power flow calculation. According to above this paper presents a global flow calculation based on distribution network power prediction. Construct boundary power predicting function and then build master-slave splitting iteration flow model and predicting iteration flow model for being used interchangeably. The distribution network power flow and boundary node voltage are obtained by master-slave splitting iteration and then power prediction function which reduce the iteration of master-slave splitting by predicting iteration can be obtained. The prediction function will be revised during master-slave iterative computation so that convergence result can be accurate. Modifying initial value of distribution network flow calculation with revising function makes initial value closer to the real value, which help reduce iteration of distribution network calculation. The results of practical example show that the proposed algorithm can significantly reduce the computing time while its result is of little error.