The invention relates to an excrement insect culture device capable of automatically separating insects from excrement and a culture method thereof. The device and the method are used for culturing maggot excrement and insect excrement in a large amount and capable of achieving automatic separation of insect excrement. The culture device mainly comprises a culture pool, the bottom of the culture pool is of a gravel cement structure, the peripheral wall of the culture pool is of a brick mixing structure, the pool face of the culture pool is provided with a slope, two sides are high, and the middle is low. A water discharge pipe as long as the culture pool is embedded under the low middle of the culture pool, sewage discharge holes vertically connected with the water discharge pipe are arranged above the water discharge pipe at intervals, and an insect collection bag capable of leaking water is sleeved in the sewage discharge holes. A row of plate blocks are arranged above the middle water discharge pipe of the culture pool, the laying length of the plate blocks is identical with that of the culture pool, and excrement is arranged in ridge in the culture pool. The excrement insect culture device has the advantages of reducing device construction cost of insect culture by excrement, reducing employment cost, improving insect breeding efficiency and being high in space utilization ratio, simple in structure, capable of conducting mechanical large-scale production, capable of automatically separating insect and excrement and conveniently collecting insects, easy in cleaning and the like.