Objective To investigate the applicative value of serum procalcitonin in non-responding community-acquired pneumonia.Methods Retrospectively analysis of non-responding pneumonia between January 1st 2009 and June 1st 2010.Results Causes of non-responding pneumonia were antibiotic failure(55.9%),mis-diagnosis(29.4%),and 5 cases with unidentified origin.Conclusion Serum procalcitonin is implicative of causes and therapy of non-responding pneumonia.