Biological fertilizer screening device

The utility model provides a biological fertilizer screening device, and belongs to the field of biological fertilizer screening. A screening assembly; the screening assembly comprises a first screening drum which is movably connected into the screening box and is obliquely arranged, a second screening drum is coaxially arranged outside the first screening drum, a third screening drum is coaxially arranged outside the second screening drum, the first screening drum, the second screening drum and the third screening drum are synchronously driven by a driving mechanism, and meshes are gradually reduced; biological fertilizer is screened step by step through the first screening drum, the second screening drum and the third screening drum and discharged out of the screening box, a support is installed in the screening box, and the third screening drum penetrates through the support and is rotationally connected with the support. The motor drives the first screen drum, the second screen drum and the third screen d