In this paper，perturbation technique is introduced into the method of Harmonic Balance. A new and effective method called Perturbation-Harmonic Balance is obtained. A great deal solutions and the order of harmonic coefficients do not need to be known previously，using the method imcomparable to the method of Harmonic Balance. On the other hand，the procedure of solving nonlinear oscillations becomes very simple. Using the method it is not related to solution of differential equation，and then it is superior to Lindstedt-Poincare and multiple scales.