The invention belongs to the technical field of municipal engineering and environment protection and specifically relates to a rain sewage damming and self-cleaning type sand settling device. The device comprises a conical catch basin, an inverted siphon, a control well, a check valve and a float ball mechanical gang control device. At the initial stage of rainfall, rainwater entering into the conical catch basin and the deposit in the well pass through a sand settling outlet at the bottom of the conical catch basin, are dammed by the inverted siphon and enter into a municipal wastewater pipe network. Along with the lasting of the rainfall, the water level in the communicated control well is constantly increased under the effect of the increasing of the water level in the conical catch basin, and then the float ball in the well rises and a gear is linked to drive a horizontal control baffle to horizontally move and open the annular check valve, and meanwhile, the inverted siphon in the conical catch basin is closed. The rainwater in relative low concentration enters into the receiving water through the municipal wastewater pipe network.