This experiment was designed to observe the proliferative effects of platelet derived wound healing factor (PDWHF) of different concentrations on fibroblasts from rat wounds and on epithelial from human wounds. Cultured fibroblasts from rat wound and epithelia from human wound were randomly divided into three groups. (1) In blank control, the cells were treated with basic medium (BM, contains 1640/0.5% FCS); (2) the positive control, the cells were treated with 1640/10% FCS and (3) in the PDWHF group, the cells were treated respectively with BM/1% PDWHF, BM/3% PDWHF, BM/5% PDWHF, BM/7% PDWHF, BM/10% PDWHF, BM/12% PDWHF, respectively. The Cells were collected after 48 hours culturing with BM or PDWHF, and the cell proliferation was measured by MTT method according to the OD values. The result showed that the PDWHF could remarkably enhance the proliferation of fibroblasts and epithelial cells when its concentration was between 1% and 7%, which was obviously higher than that of the blank control (P lt; 0.01). When the concentration of PDWHF reached 10%, its proliferative effect was not remarkable when compared with the blank control, When the concentration of PDWHF reached 12%, it showed inhibitory effect on fibroblasts and manifested no obvious inhibitory effect on epithelial cells. It was concluded that the PDWHF was a combination of a variety of growth factors. In a certain range of concentration, the PDWHF might effectively promote the proliferation of fibroblasts and epithelial cells. Howerve, when its concentration reached to relatively higher level, its effect was not remarkable any more, or even showed inhibitory effect on cell proliferation.