The disclosure provides a stochastic look-ahead dispatch method for power system based on Newton method, belonging to power system dispatch technologies. The disclosure analyzes historical data of wind power output, and uses statistical or fitting software to perform Gaussian mixture model fitting. A dispatch model with chance constraints is established for system parameters. Newton method is to solve quantiles of random variables obeying Gaussian mixture model, so that chance constraints are transformed into deterministic linear constraints, thus transforming original problem to convex optimization problem with linear constraints. Finally, the model is solved to obtain look-ahead dispatch. The disclosure employs Newton method to transform chance constraints containing risk level and random variables into deterministic linear constraints, which effectively improves model solution efficiency, and provides reasonable dispatch for decision makers. The disclosure is employed to the dispatch of the power system including large-scale renewable energy grid-connected.