Giving a high precise Short-term wind speed Multi-step forecast for wind farms,which can effectively relieves disadvantageous impact of wind power plants on power systems,enhances the competitive ability of wind power in electricity market.This work proposes to analyze the available horizon of the multi-step wind speed forecasting and improve the forecasting accuracy in this specific horizon.The final horizon is determined through analyzing the ACF of each sub-series decomposed by wavelet transform.Each sub-series NN model has different horizons and then a multiresolution ensemble strategy is ensured.