Abstract: OBJECTIVE To investigate the changes of blood coagulation and fibrinolysis in the development of community acquired pneumonia patients with different conditions, so as to provide reference for clinical diagnosis and treatment of the disease. METHODS A total of 160 cases of patients with community-acquired pneumonia pneumonia were selected in our hospital from Jun. 2013 to Jan. 2016 as pneumonia group, and the other selected 160 cases of healthy people for the same period in control group, and according to pneumonia severity index (PSI) the pneumonia group was divided into high risk, medium risk, low-risk patients compared with the control group the different conditions of coagulation and fibrinolysis indicators. RESULTS Pneumonia patients antithrombin Ⅲ (AT-Ⅲ), platelet count (PLT), thrombin time (TT) were significantly lower than the control group, but fibrinogen (FIB), activated partial thromboplastin time (APTT), prothrombin time (PT) were higher (P<0.05). Pneumonia patients of D- dimer (DD), fibrin (original) degradation products (FDPs), tissue plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1 ), neutrophil elastase (NE) and other fibrinolytic indexes were significantly higher than control group(P<0.05). High-risk, medium risk and low risk patients AT-Ⅲ, PLT, TT increased in turn, but APTT gradually decreased (P<0.05) between groups. Different PSI index patients FIB and PT was no significant difference. High-risk, medium risk and low risk patients D-D, FDPs, t-PA, PAI-1, NE and other fibrinolysis indicators were in turn reduced (P<0.05). The community-acquired lung infections in patients with FIB, APTT, D-D, FDPs and other coagulation and fibrinolysis indicators are higher than normal levels, CONCLUSION and the more severe the disease, the higher the degree of abnormality in coagulation and fibrinolysis indices.