In the background of inefficient indicators for early diagnosis of pneumonia in adults, Objective Explore the utility of PCT, CRP, CD64 and Routine Blood Parameter in diagnosis of bacterial pneumonia in adults. Methods From January 1, 2019 to December 31, 2019, 191 adult bacterial pneumonia patients diagnosed and treated in the affiliated Hospital of Inner Mongolia University for Nationalities and 99 healthy people were selected as study subjects. A total of 191 adult bacterial pneumonia patients were treated as the case group, and 99 healthy physical examination patients were treated as the control group. PCT, CRP, CD64 and blood routine test parameters were compared between them. Correlation analysis and multiple linear regression analysis were used to explore the differential factors of adult bacterial pneumonia, and ROC curve was used to analyze the effectiveness of each indicator in the differential diagnosis of adult bacterial pneumonia. Results PCT (4.95±2.462), CRP (33.53±9.342), CD64 (9.26±4.023), N/L (9.54±3.878) and N% (1.16±0.632) in the case group were significantly higher than (0.22±0.059), (3.29±1.712), (1.91±0.600), (2.66±0.665) and (0.66±0.158), those of the control group. There were no statistically significant differences in other indicators.