Abstract: The credible capacity is an important index to measure the contribution of renewable energy to the generation capacity of the power grid and is extremely important to the planning and regulation of power grid containing new energy system. Considering the fact that there exists a certain correlation between the new energy output and load in the same region, a method to assess credible capacity of new energy, in which the source-load matching characteristics was taken into account, was proposed. Based on the kernel density estimation the new energy output probability model was acquired, and the Copula function was used to describe the correlation between renewable energy and load in seasonal scenarios, and a source-load joint probability density distribution model was constructed to generate source-load correlation output scenarios. Based on reliability index and credible capacity characteristic index the assessment on credible capacity was performed. Finally, the effectiveness of the proposed method is verified by the analysis on practical example of a certain region.