Abstract: OBJECTIVE To evaluate the diagnosis value of C-reactive protein(CRP) in patients with community acquired pneumonia(CAP). METHODS A retrospective study was performed on 611 randomly selected patients in fever clinic of Xuanwu Hospital during one year(2011-02-01-2012-01-31). All patients were detected by the QuikRead of CRP. RESULTS In 611 patients, CRP was elevated(>10 mg·L^-1) in 394 cases (accounting for 64.5%) in which patients with pneumonia accounted for 16.50%, while 217 patients with normal CRP level(≤10 mg·L^-1) had low proportion of CAP patients (accounting for 4.15%). There was significant difference(P<0.05). When CRP levels >30 mg·L^-1, there were about 1/5 patients diagnosed with CAP, and CRP levels >50 mg·L^-1, there were about 1/4 patients diagnosed with CAP. The sensitivity of CRP on the diagnosis of pneumonia was 87.84%. Total positive predictive, negative predictive value of CRP rapid test was 16.50% and 95.85%, respectively. CONCLUSION In fever clinic, the levels of CRP show a significant correction with the diagnosis of CAP, and negative predictive value of CRP testing is higher.