The invention discloses a reactive power optimization control method of distribution network. The traditional reactive power optimization model is based on definite system conditions without considering the uncertain factors. The invention utilizes moth flame optimization algorithm to solve reactive power optimization control problem of distribution network, maps control variable from each moth toload flow date, and then calculates load flow to obtain transmission loss through matpower software; at each iteration, the update position of each moth is relative to the flame, and after the updateposition, the transmission loss of the corresponding moth is obtained; updated control variables are checked to see if they exceed the limit, and if they do, they are marked at the lower and upper limits for accurate results; 3) The evaluation process is repeated until it is terminated by the maximum iterative algebra restriction. The invention does not need many control parameters when solving the reactive power optimization dispatching problem, and the optimization method is simple and easy to implement.