Abstract: The performance of the recycled cement concrete is influenced by a great deal of factors,such as compressive strength of recycled aggregates,water content,replacement ratio etc.This test uses the Auto PoreⅣmercury porosimeter to analyze the microstructure and performance of recycled concrete with different mixing proportion of recycled aggregate.Studies have shown that if the mixing proportion of the recycled aggregate is less than 60%,then some properties,such as slump of the recycled concrete,compression strength etc.,will drop to some extent.Through adjusting mixing proportion can meet the specification requirement.