The invention relates to a device for determining water and soil loss of a vertical green wall. The device comprises a vertical green wall module, a loss collection and weighing module and an artificial rainfall module, wherein the vertical green wall module is composed of steel framework planting module units and planting grooves; a load digital display system in the loss collection and weighing module is connected with a pressure sensor and is used for obtaining water and soil weight in a collection groove; a rainfall monitoring controller in the artificial rainfall module is used for obtaining and controlling pressure and a rainfall value through connecting with a pressure water pump, a pressure feedback device and a rain gauge. The device for determining the water and soil loss of the vertical green wall, provided by the invention, is used for completely simulating the structure of the vertical green wall, and the rainfall with different intensity is artificially simulated, so that a water and soil loss condition is determined in real time when different types of soil and different plants are applied to the vertical green wall, and the problem that planting soil or matrixes of the vertical green wall are difficult to screen is solved; meanwhile, a basis is provided for selecting the plants of the vertical green wall, and support is provided for improving the persistence of the vertical green wall.