Objective To investigate the cause, diagno sis and treatment of acute acalculous cholecystitis(AAC).Method 32 cases of AAC which were treated from 1990 to 2000 were analyzed retrosp ective ly.Results 25 cases were diagnosed by B-ultrasonograph ,th e positive rate of diagnosis was 88.0%(22/25),7 cases were diagnosed by CT,6 c ases were definitely diagnosed(85.7%).All of them underwent operations, cholec ystectomy was performed in 29 patients,cholecystostomy in 2, subtotal cholecyste ctomy in 1 .Of them 31 were cured and one died.Conclusions The cause of AAC is very complication, the preoperative diagnosis is difficult, it is easy to be misdiagnosed. Surgeon should pay more attention to AAC. B-ultra sonograph is the first choice of the diagnosis of AAC,CT can give a hand to diag nosis. The early operation resection is the most effective method.