Abstract: Research is conducted on the unit commitment optimization after HEVs mass connected to the power system. HEVs charge and discharge quantity and thermal power unit output in each period are used as optimizable scheduling variables and the coal-fired minimum cost of thermal power generating unit as the objective function. And under the use of complementary constraints and optimization extreme value theory, transforming unit combination problem into nonlinear programming for continuous space, a complementary constraint optimization model of power system unit combining HEVs mass into the network is established. Then the smooth NCP function is used to deal with the complementary constraint optimization model, which is transformed into a general nonlinear programming problem, and the solution is solved by using the primal dual interior point method. A simulation experiment is carried out with the optimal combination of the units in the 10 unit system 24 h as an example to verify the validity and feasibility of the proposed algorithm.