Under a spot pricing based electricity market environment，a centralized charging strategy of plug-in hybrid electric vehicles（PHEVs）is proposed based on demand side response.A mathematical model is established taking into account the valley-filling effect of supply side and the userscost.A dynamic estimation interpolation based algorithm is designed to optimize the mathematical model.Finally，a simulation based on an areas predicted data of year2020is made to show that，the proposed centralized charging strategy can not only lower the peak-valley difference，but also save userscost，and achieve a win-win result.