Abstract: The uncertainty of the source and load increases the difficulty of real-time situation awareness of the distribution network. To this end, an affine power flow calculation for the low-voltage distribution network considering the uncertainty of distributed photovoltaic output is proposed. The power flow model of the low-voltage distribution network is established considering uncertainty of photovoltaic output and load. The influence of the neutral point voltage on the power flow calculation results is considered, and the affine expression of the distribution network state is established, thereby reducing the expansion effect of the interval operation and obtaining a more compact interval of the state variables. Based on the standard distribution network test system, the proposed method is. The simulation results show that the proposed method can not only improve the calculation accuracy but also give more valuable evaluation results in the analysis of power quality.