Abstract: Objective To investigate the effects of rapamycin on p-JAK2,STAT3, p-STAT3 and PCNA in ranal tissue of IgAN rats.Methods Establish animal models of IgA nephropathy .The experiment is devided into control group,IgAN model group,losartan group and rapamycin group.The clinical efficacy of rapamycin,and its influences on the protein and mRNA expressions of STAT3,p-STAT3,p-JAK2 and PCNA were determined by western blot,RT-PCR and immunohistochemical techniques,respectively. Results The protein and mRNA expressions of p-STAT3, STAT3, p-JAK2 and PCNA were significantly increased in kidney tissue of IgAN rats. (p<0.01);Rapamycin down-regulationed these excessive expressions. ( p<0.01). Conclution Rapamycin may extenuate the pathological change of IgAN rats by inhibiting JAK/STAT signaling pathway, activation of STAT3 and mesangial proliferation.