Voltage quality may be influenced due to large-scale charging loads connecting to residential distribution network, it is necessary to establish an effective charging load model to study the impact of electric vehicle charging on the voltage quality of distribution network, and provide the theoretical basis for the upgrading of distribution network and the reasonable construction of charging pile. Firstly, a calculation method of private car charging load considering the charging high peak effect at the weekend is proposed, and a more accurate charging load curve can be obtained using this method. And then, the model of distribution network is established in MATLAB. The influences of different scales of electric vehicles assess to the network on the node voltage deviation and voltage unbalance and are simulated and analyzed, in the process of simulation, different scenes are designed. The different influences of fast charging and slow charging, battery-electric and plug-in electric vehicle charging on the distribution network are considered. At the same time, the effects of slow charging in three-phase balanced charging and unbalanced charging mode on the three-phase voltage unbalance are considered as well.