Objective To explore imaging feature of muscle crush injury of extremity on contrast enhanced ultrasound (CEUS) by an animal experiment.Methods Twenty-eight New Zealand rabbits were anesthetized by intramuscular pentobarbital sodium (30 mg/kg).A special balloon cuff device was used to create left hind leg crush injury with a force of (18.6 kPa).23 of the 28 rabbits had crush injury of extremity and survived for 72 hours.CEUS evaluated infusion model and contrast intensity in crush region of hind leg at the 0.5,2,6,24 and 72 hour after the release of the crushing pressure.Peak intensity (PI) was analyzed by comparing with serum creatinekinase (CK) and myoglobin (MYO).Results Twenty-three rabbits presented that the area of crushed region in left hind leg was 60 cm2,accounting for 2.6％-3.0％ of body surface area.In different time after decompression,the crushed regions showed rapid enhancement and the intensity was higher than that of no-crushed region.The time-intensity curves of crushed regions all appeared as fast wash-in and slow wash-out.PIs of rushed regions were higher obviously than those of nocrushed regions (P ＜0.001).ROC curves were employed in diagnosis value of PI for crushed region.And PIs showed positive correlation with CK and MYO and the correlation coefficient was 0.833-0.996.Conclusions CEUS presents that the micro-circulation perfusion of the crushed muscle increased obviously after the release of the crush pressure.PIs evaluated quantitatively the micro-circulation perfusion changes.It suggests a potential alternative for evaluating micro-circulation abnormality and ischemia reperfusion injury of the muscle crush injury to extremities.