The invention belongs to the field of civil engineering and relates to a measuring device and a measuring method for erosion resistance of a soil slope under an erosion falling condition. The measuring device comprises a temperature-varying and humidity-varying box and an internal cylindrical supporting frame, an external cylindrical supporting frame, a meshed metal square grid, a metal grid plate and a scale which are all arranged in the temperature-varying and humidity-varying box, wherein the meshed metal square grid is arranged at the top of the internal cylindrical supporting frame; the metal grid plate is arranged at the top of the external cylindrical supporting frame; the external cylindrical supporting frame covers the external part of the scale; the internal cylindrical supporting frame passes through the metal grid plate and then is arranged on the scale; the sum of the heights of the internal cylindrical supporting frame and the scale is more than the height of the external cylindrical supporting frame; a to-be-measured slope soil sample is arranged on the meshed metal square grid. The measuring device provided by the invention can be used for evaluating the erosion resistance of the soil slope by effectively utilizing laboratory equipment, relieving the workload and reducing cost of field test.