In this paper, according to the ‘Technical rule for connecting wind farm to power system’ promulgated by the state, the least squares support vector machine (LSSVM) algorithm is used to build a mathematical model, and six indicators, namely, voltage deviation, voltage fluctuation, voltage flicker, grid harmonics, frequency deviation and three-phase voltage imbalance, are comprehensively considered and a certain quality level is calculated, which is used to evaluate the power quality of wind power stations and substation access points. LSSVM is a classification method based on the principle of minimizing institutional risk and combined VC dimension theory. Compared with traditional classification method, LSSVM has the advantages of low complexity, short training time, high accuracy and the like. According to the electric energy data provided by Weifang power grid, the accuracy and practicability of this evaluation method are verified.