Objective To investigate a new automatic inverse optimal solution based on VMAT optimization model and verify its result.Methods A variant of the new automatic inverse optimal solution was proposed in this study,which provided a solution to calculate treatment plan with the minimized number of beams and the minimized levels of their intensities on the basis of VMAT optimization model by customized software tools.The verifications were evaluated on the simulated head-neck phantom by dosimetric parameters.Results Compared with conventional IMRT/VMAT treatment plans,the adaptive optimization program(AOP)plan showed that plan20/40(20 fields with totally 40 sub-fields,m=2)made the best achievement and it was clinicable.Conclusions The proposed new optimization technique provides an effective way to reach an inverse treatment plan with the best compromise and less sub-fields compared with IMRT/VMAT plans.