In order to improve the comprehensive operating benefits of the CCHP-type microgrid, an optimization model with minimum operating cost and CO2 emissions is established. In order to deal with the uncertainty of source-load, a typical scene acquisition method based on the overall generation and reduction of error scenes is proposed. The Pseudo F-statistics (PFS) index is introduced to determine the optimal number of scene reductions. The example calculation shows that compared with the deterministic optimization method which does not consider the source-load uncertainty, the method proposed in this paper has a better effect in dealing with that uncertainty. The operating cost is reduced by 0.31%, and the CO2 emissions are reduced by 4.85%. In addition, the calculation example shows that applying the PFS index to determine the optimal number of clusters can find the balance between the model's ability to deal with uncertainty and the calculation time, and improve the calculation efficiency of the model. This work is supported the Key Research and Development Plan of Shaanxi Province (No. 2018ZDCXL-GY-10-04) and the Research Fund of the State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology (No. 2019KJCXTD-10).