Small particulate matter separating device

A small particle matter separating device comprises a water collecting tank, a filtering assembly, a liquid inlet, an overflow port and a sewage draining exit, the sewage draining exit is formed in the bottom of the water collecting tank, the filtering assembly comprises a filtering net, a filtering net guide pipe is arranged in the filtering net, and the filtering net is detachably and fixedly connected with the filtering net guide pipe. The upper end of the filter screen guide pipe and the lower end of the filter screen guide pipe extend out of the filter screen upwards or downwards respectively, suspension to be separated containing small particle substances enters the water collecting tank from the filter screen guide pipe, freely passes through grids arranged on the middle section of the filter screen guide pipe, enters an area between the filter screen guide pipe and the filter screen and is separated from the filter screen. Particles larger than meshes of the filter screen are blocked in the filter scr