Five different kinds of rice liquid were added to traditional lime mortar. The consistency, surface hardness, compressive strength, shrinkage, freeze thaw resistance and microscopic structure of lime mortar added with different kinds of rice liquid were measured to investigate the influence of rice liquid type on properties of lime mortar and their action mechanisms. Results indicate that the addition of sticky rice, waxy yellow rice, black sticky rice, rice and sorghum rice liquids reduces the consistency and shrinkage of lime mortar and increases their surface hardness, compressive strength and freeze thaw resistance. Among the five different rice liquid lime mortars, the combination properties of the waxy yellow rice liquid lime mortar is the best. Compared with pure lime mortar, the 28d and 60d compressive strengths of waxy yellow rice liquid lime mortar increase by 1036% and 694% respectively, and the freeze thaw resistance increases by 150%. It is suggested that the waxy yellow rice liquid can be added as the organic additive for conservation of historical masonry buildings. The good mechanical property of the rice liquid lime mortar, which could be explained by its compact structure, is relevant to the content of amylopectin in rice liquid.