as the installation scale of distributed generations in the distribution network continues to increase, the distribution network has more flexible scheduling resources. However, a large number of power electronic devices in distributed power generations pose a threat to the power quality of the distribution network. Based on the frequency coupling matrix, a harmonic optimal power flow model considering harmonic coupling factors is established. Using the method of convex relaxation, the original non-convex model is transformed into a semi-definite programming model that can be solved by mature planning software. An actual township distribution network example is used to verify the rationality of the model proposed.