The invention provides a semiconductor microcavity laser structure and a preparation method thereof. The microcavity laser is prepared on the nitrogen surface of the nitride semiconductor, and the p-type ohmic contact of the (0001) gallium surface adopts the whole-surface contact method, which greatly reduces the cost of the microcavity laser. The series resistance of the microcavity laser; the heat of the microcavity laser is directly conducted to the heat sink with high thermal conductivity, and the microcavity laser is prepared on the nitrogen surface, and the side wall of the microcavity laser is fabricated by wet etching, which can greatly improve the stability of the microcavity laser properties, using AlInGaN, ITO, AZO, IGZO, porous GaN, Ag, Al, ZnO, MgO, Si, SiO 2 , SiNx, TiO 2 , ZrO 2 , AlN, Al 2 o 3 、 Ta 2 o 5 , HfO 2 , HfSiO 4 , AlON material is used as the optical confinement layer of the microcavity laser to provide strong optical confinement. The novel nitride semiconductor microcavity laser structure proposed by the present invention has the advantages of small resistance, low thermal resistance, easy implementation of electric injection, good stability and reliability, etc., and can greatly enhance the performance and service life of the nitride semiconductor microcavity laser.