The invention discloses a post-evaluation method of the construction effect of a power distribution network project, based on a BP neural network. The post-evaluation method includes the steps: S1, establishing an evaluation index system; S2, acquiring base index data and preprocessing; S3, through scoring of experts, obtaining the target scores corresponding to Ntrain training samples; S4, determining the network layer number; S5, determining the network node number; S6, determining a transfer function; S7, selecting a training method; S8, establishing a BP artificial neural network post-evaluation model; S9, setting a training parameter, and training; S10, judging the training effect; S11, inspecting the trained BP artificial neural network post-evaluation model; and S12, observing the fitting effect. The established BP artificial neural network post-evaluation model of the post-evaluation method of the construction effect of a power distribution network project, based on a BP neural network can fully absorb the determination experience of experts so as to save the step of weight determining and scoring, so that the evaluation becomes more concise and clear.