Abstract: objective: To observe the effect of ultrashort waves towards the free skin flap taken by dermatome of post burn skin. Method: Thirty-two cases of stamp-like split skin graft in self-comparison and 40 cases of split thickness skin graft is divide into two groups according to receiving ultrashort waves treatment, the treatment group received no heat-free ultrashort waves treatment post-operation, the control group not received ultrashort waves treatment.Result: Comparison was done according to skin graft survival rate by two groups, the wound healing time of treating group with ultrashort waves is shorter than that of control groups (p<0.01).And the blister of treating group with ultrashort waves is decreaser than that of control groups(p<0.05).Conclusion: After dermatoplasty no heat-free ultrashort waves treatment can conduced to promote free skin graft survival.