Abstract: According to relevant standards, guide rules and characteristics of 10 kV power distribution networks, this paper analyzes parameters of capacity-load ratio of the power distribution transformer and makes suitable amendment. By using back propagation (BP) neural network algorithm, it obtains mapping relation between load coincidence factor and major influencing factors and the optimal load dispersion coefficient. Combining with regional actual examples, it shows determination method for capacity-load ratio of the 10 kV power distribution transformer which fully considers characteristics of regional load and avoids blind execution in the whole province and cities according to guide rules or standards.