The invention discloses a method for forecasting the displacement of surrounding rocks of a tunnel by utilizing a neural network, which comprises the following steps: an appropriate neural network model is selected, a training sample of the displacement data of the surrounding rocks is input, training is carried out to the neural network , the neural network model with the precision which meets the requirements is obtained, the forecast of the displacement of the surrounding rocks is further carried out by utilizing the trained neural network, the neural network calculates and outputs the forecasted displacement of the surrounding rocks within the following 3 to 5 days of the construction time according to the input measuring point input vector, thereby realizing pre-warning of the displacement of the surrounding rocks. The method utilizes the credible monitoring data in the actual construction, considers the geological features and the related influencing factors of the construction region and carries out the forecast of the deformation and the internal force, etc., of the rocks in the next stage by the feedback analysis of the neural network, thereby guiding the construction, optimizing the construction parameters and reasonably arranging the working procedure.