Objective To investigate an effect of compressive stress on proliferation and apoptosis of human hyperplastic scar fibroblasts（HSFb） in vitro. Methods HSFb were obtained from a 20 year old female patient who developed a hyperplastic scar 3 months after operation for a largearea burn. HSFb were isolated, and were cultured in vitro with the simplified airpressure controlled cellculture instrument, and then they were randomly divided into the following 8 groups: the control group (no stress) and the 7 continuous compressive stress groups, which respectively underwent the 5, 10, 15, 25, 50, 100 and 150mmHg(1mmHg=0.133 kPa) pressure treatment for 4d ays. The absorbance (A) of the cell and the inhibition ratio (IR) of the cell proliferation were determined by the MTT assay, the cell growth cycle was determined by the flow cytometer, and the cell apoptosis was observed by the AnnexinV binding with PI labeling method. Results In the 5, 10, 15, 25, 50, 100 and 150mmHg pressure groups and the control group, the A values of the cells were 0.228±0.004, 0.226±0.003, 0.213±0.005, 0.180±0.005, 0.172±0.007, 0.165±0.004, 0.164±0.004 and 0.230±0.005, respectively; the IRs of the cell proliferation were 0.8%，2.0%，7.3%，21.7%，252%， 28.2% and 0, respectively;the ratios of the cells in G1 were 71.80％±0.44％, 72.32％±0.40％, 74.56％±1.01％, 82.82％±2.76％, 86.77％±2.06％, 88.23％±1.27％, 89.11％±1.74％ and 71.6％±0.49％,respectively; the cell apoptosis ratios were 4.22％±0.49％, 5.12％±0.74％ , 8.58％±0.79%, 19.28％±1.40%, 25.60％±1.21%, 3580％±2.39%, 36.18％±2.38% and 4.00％±0.36％, respectively. In the 5 and 10mmHggroups there were no statistically significant differences in all the above parameters when compared with those in the control group (P＞0.05); however, in the 15, 25,50, 100 and 150mmHg groups there were statistically significant differences in the above parameters when compared with those in the control group (P＜0.05). Furthermore, in the 10, 15, 25 and 50 mmHg groups, there were statistically significant differences in the Avalue of the cells and the ratios of the cells in G 1 when compared with each other (P＜0.01). By contrast, there were no statistically significant differences in the 50, 100 and 150 mmHg groups when compared witheach other (P＞0.05). In the 10, 15, 25, 50 and 100mmHg groups there werestatistically significant differences in the cell apoptosis ratio when comparedwith each other (P＜0.01). In the 100 and 150 mmHg groups there were no such statistically significant differences when compared with each other (P＞0.05).Conclusion A continuous compressive stress when given properly can have a combined effect of the proliferation inhibition and the apoptosis promotion on HSFb in vitro, and this kind of combined effects can becomeone of the important mechanisms for the pressure therapy in treating hyperplastic scar.