A dilution and filtration device comprises: a sampling member comprising a suspension collecting chamber having at least one suspension collecting window disposed at a side surface of the suspension collecting chamber; a top cap having a through hole at a center portion of the top cap; a connecting cylinder disposed at a top end of the sampling member and mounted to the through hole of the top cap such that the connecting cylinder is concentric with the through hole and is rotatable; and a specimen tube connected to the top cap and accommodating the sampling member. An apparatus of preparing excrement detection solutions comprising the dilution and filtration device and a method of preparing excrement detection solutions using the dilution and filtration device are also provided.