Based on the analysis of influence factors on boundary angle of surface movement in coal minegoaf,this paper presents a method used to predict the boundary angle by the BP Artificial Neural Network.A prediction model of the boundary angle is constructed with BP Artificial Neural Network.Data of the boundary angle from 30 practical engineering projects are used as the assembly of training samples of Neural Network.The prediction model is then validated using data from practical engineering projects.Results from the validation show that prediction precision for the boundary angle is up to 90%,indiicating that the prediction method based based on bp artificial neural network is very useful and feasible in engineering.