This　paper　proposes　a　photovoltaic　(PV)　array　simulator　based　on　the　topology　of　the　buck　converter　and　digital　control　strategy.　First　of　all,　a　photovoltaic　array　simulation　model　is　established　by　analysis　of　current-voltage　characteristic　curve　of　the　photovoltaic　cell　array.　To　simplify　the　control　model,　the　output　current-voltage　simulation　curve　is　piecewise　fitted.　The　buck　convertor　is　controlled　by　different　duty　ratio　of　pulse-width　modulation　(PWM)　and　outputs　current-voltage　curve　in　line　with　the　fitted　curve.　Experimental　results　and　simulation　results　prove　the　rationality　of　the　design.