Nowadays, SVM prediction model based on phase space reconstruction is widely used, and it also plays an important role in urban water supply prediction. The traditional prediction model tends to bring the reconstructed phase space into the whole, which may lead to ineffective introduction of SVM. Phase prediction method is used to improve the accuracy of prediction. Based on this, the evolutionary tracing method is introduced into the prediction model of phase space reconstruction to filter the effective points and to optimize the training samples of the prediction model. The evolutionary tracing method is used to forecast the urban water supply quantity by using MATLAB programming software. The average absolute error of forecasting result is reduced from 0.52% to 0.29%, which proves the availability and effectiveness of evolutionary tracing method.