 Reconstruction of large scale skin defect is a challenge to clinical surgeons. Soft tissue expansion has won wide attention in recent years as it promotes skin regeneration with perfectly matched tissue. However, some patients with poor skin regenerative ability would suffer from skin flap over-thinned and even necrosis under the continuous stretching by silicone expander. This study is to evaluate the effects of autologous fat graftSVF transplantation on accelerating skin regeneration and promoting tissue expansion process. 