Abstract: Distributed photovoltaics are greatly affected by weather conditions, and calculating the carrying capacity of distributed photovoltaics in 110 kV power supply areas is of great significance for regional power supply. A calculation model of distributed photovoltaic carrying capacity for 110 kV power supply areas based on classification and regression trees（CART） is proposed to address this issue. This model is based on the output power of distributed power sources, the proportion of regional distributed power generation, and the incremental line loss of local distributed power sources, etc. Using the CART decision tree, a calculation model of the distributed photovoltaic carrying capacity for 110 kV power supply areas is established, and the improved whale optimization algorithm is used to solve the calculation results. After experimental testing, it is found that the model has higher accuracy in calculating the distributed photovoltaic carrying capacity. This indicates that the method can effectively calculate the distributed photovoltaic carrying capacity of different experimental areas in different seasons, and has high application value.