Abstract To study the regulation of growth and proliferation of tissue-repair cell from wound microenvironment, the effects of wound fluid (WF) on the growth and proliferation of wound fibroblast were studied in vitro. Thirty rats were divided into 6 groups. On the back of every rat, an incision of 0.5～1.0cm was performed a subcutaneous sac was made by blunt dissection. A piece of sponge was put in, and the wound was sutured. After 1,3,7,9,11,15 days, one group of the rats were sacrificed respectively, and WF was collected from the sponge. Two kinds of medium were made with each WF: 1640+1%FCS+10%WF and1640+10%FCS+10%WF. After 48 hours incubation with newly prepared wound fibroblasts, the growth of the cells was observed. It was shown that (1) Under 1%FCS, WFfrom1,3,7 days stimulated cell proliferation, and WF from 9,11,15 days caused cell death. (2) Under 10%FCS, WF from 9,11,15 days inhibited cell growth. It was suggested that the wound microenvironment stimulated the fibroblasts to proliferate for one week after injury, and beyond that further growth seemed to be arrested, and that there might be some growth inhibitory factors present in the microenvironmentduring the late stage of wound healing.