Objective:To study the effects of water extracts from different processed products of Rhizoma Polygonati (RP) on rat model of qi and yin deficiency, and to provide reference for scientific processing and clinical rational use of the drug. Methods69 SD rats were randomly divided into normal group and model group. The rat model of qi and yin deficiency was established considering three factors (gavage administration of medicine hot in property, food restriction and weight-bearing swimming) for 2 weeks. 42 rats with successful modeling were randomly divided into model group, positive group, commercial RP group, four-fold processed RP group and nine-fold processed RP group. Each group was given 10 g/kg of water extracts from different processed products or positive drug (Shengmai Drink) for 6 weeks. The general behavioral indicators were observed during administration, including body mass, diameter of tail root, face temperature, grip strength, pain threshold and thermal imaging. After last administration, blood samples were collected from tail root to determine hemoglobin; and blood samples were collected from orbital vein to determine alanine aminotransferase (ALT),aspartate aminotransferase (AST), glucose (GLU), triglyceride (TG) and creatinine (Cr) in blood, and to determine immunoglobulin A (IgA), immunoglobulin M (IgM), adenosine cyclic phosphate (cAMP) and guanosine cyclic phosphate (cGMP) in serum by ELISA.  Results:After 2 weeks of modeling, compared with the normal group, there was significant decrease in body mass, GLU, and Cr in the model group, indicating successful modelling. After 6 weeks of administration, compared with the normal group, the indicators (except ALT) were significantly different in the model group (P<0.05, P<0.01); there were significant decrease in tail diameter and GLU and increase in face temperature in the commercial RP group (P<0.05, P<0.01); there were significant decrease in tail diameter and increase in TG in the nine-fold RP group (P<0.01). Compared with the model group, all processed products of RP could improve the general signs (grip strength, diameter of tail root, face temperature, thermal imaging and pain threshold), liver function (decrease in AST and ALT) and glycolipid metabolism (decrease in TG and increase in GLU), increase serum IgA and IgM, and regulate the cyclic nucleotide system of rats with qi and yin deficiency. Commercial RP had desirable effect in improving thermal imaging, immune function and the cyclic nucleotide system (P<0.05, P<0.01). Four-fold processed RP had statistical significance in improving general signs, liver function, glycolipid metabolism, immune function and the cyclic nucleotide system (P<0.05, P<0.01). Nine-fold processed RP significantly improved liver function (P<0.01).  Conclusion:Different processed products of RP can improve the symptoms of qi and yin deficiency in rats. Four-fold processed RP has better effect in increasing body mass and tail diameter of the rats with qi and yin deficiency, and it is better at regulating glycolipid metabolism in rats.