Abstract: Objective: To investigate the clinical effect and HSP70 expression on the wound surface of chronic ulcer of skin by laser therapy. Methods: Randomly divided the raw surface of 64 example of 84 place into traditional treatment group and laser treatment group .Laser treatment group was treated with laser therapy on the base of traditional treatment Assessment it's curative effect after 3 weeks post of all wound surface. At the same time to obtain wound tissue of 5 cases, and set of normal skin as a compare group, profess the slice of HSP70 for immunohistochemistry. Statistics analysis was progressed by counting HSP70 masculine cell and detect its gray scale value. Design the primer for RT-PCR test to detect the HSP70 mRNA expression information. Result: Two sets patients corresponding to cure was better than prior treatment but the wound healing rate and effeciency of laser treatment group is higher than tradition treatment group (P <0.05 or 0.01). And immunity class dyeing showed there was no obviously expression of HSP70 positive cell in between normal skin and chronic ulcer of skin, 3 weeks post laser treatment can observe abundant HSP70 masculine cell expression , its masculine cell count is obviously higher than other two sets (P <0.01).The gray scale of cell signal is obviously lesser than other two sets( P <0.05 ).There is no clear difference between tradition therapy group and normal control group. PT-PCR result shows that the tissue group of laser therapy had amplified a specific single band of swim band of size about 268 bp. There is no significant amplification of HSP70 m RNA gene fragment in normal control group and tradition therapy group. Conclusion: There is good clinical curative effect of the laser treatment of chronic ulcer of skin it maybe the relation between the activation of endogenous protection mechanism of wound cells heat shock and reduce infection and promote the wound healing process.