Multipactor　discharge　on　the　rectangular　grooved　dielectric　surface　is　simulated　self-consistently　by　using　a　two-and-a-half　dimensional　(2.5　D)　electrostatic　particle-in-cell　(PIC)　code.　Compared　with　the　electromagnetic　PIC　code,　the　former　can　give　much　more　accurate　solution　for　the　space　charge　field　caused　by　the　multipactor　electrons　and　the　deposited　surface　charge.　According　to　the　rectangular　groove　width　and　height,　the　multipactor　can　be　divided　into　four　models,　the　spatial　distributions　of　the　multipactor　electrons　and　the　space　charge　fields　are　presented　for　these　models.　It　shows　that　the　rectangular　groove　in　different　models　gives　very　different　suppression　effect　on　the　multipactor,　effective　and　efficient　suppression　on　the　multipactor　can　only　be　reached　with　a　proper　groove　size.　(C)　2015　AIP　Publishing　LLC.