MGCZ series single-body gravity paddy separator is feasible for separating brown rice from paddy efficiently under reciprocating movement of sieve plate according to different bulk densities, specific gravities and surface friction coefficients between paddy and brown rice. It is particularly suitable for separating mixed or low uniformity grain to improve the purity degree of brown rice. Good paddy separating effect can not only increase the whole output greatly, but also increase economic benefit enormously.