Aiming at the multiple uncertainties brought by the randomness and correlation of distributed generation, fluctuating load and line parameters to flexible interconnected distribution network, a probabilistic loss allocation method for flexible distribution network considering the time series characteristics and uncertainty of source network load is constructed. Firstly, the time series model with multiple uncertain parameters is established, and the three-point estimation method based on nataf inverse transform is transformed into AC/DC probabilistic power flow in multi-time scenario; Then, the network loss impact index system of random equipment is proposed. Based on the time scenario, the improved analytic hierarchy process entropy weighting method is used to determine the network loss change contribution rate of DG and EV charging piles. The network loss change is allocated to DG and EV charging piles based on the contribution rate, and the probability density function of allocated electricity is fitted by Cornish Fisher level, The annual network loss allocation probability density function is obtained by integrating the time scenario; Finally, the effectiveness of the proposed algorithm is verified based on the improved 33-node flexible distribution network and the improved Dongguan Songshan Lake topology.