Phase　unwrapping　is　a　key　step　of　three-dimensional　display　in　digital　holographic　microscopy　(DHM).　On　the　basis　of　the　framework　of　Lp-norm,　the　unified　mathematic　model　of　two-dimensional　phase　unwrapping　is　studied.　A　wrapped　phase　map　of　DHM　is　analyzed　with　several　phase　unwrapping　methods.　The　results　show　that　the　L0-norm　algorithm　performed　best　in　efficiency,　but　got　wrong　result　because　of　too　much　noise,　the　L1-norm　algorithm　could　achieve　an　better　resolving,　but　the　most　long　time　consuming,　the　Lp-norm　algorithm　used　much　iterative,　but　also　resulted　with　aberrations　and　the　efficiency　was　rather　low,　the　least-squares　algorithm　and　the　weighted　least-squares　algorithm　could　obtain　better　optimal　resolving　and　better　efficiency.　The　two　algorithms　are　acceptable　in　DHM.