Abstract: Objective To evaluate the quality of network reports on infectious diseases in Anning city, Yunnan province status. Methods The data on infectious diseases from 2005 to 2008 were retrieved from the Diseases Surveillance Information Reporting and Management System to calculate the timeliness of report and verification, composite index and accuracy of reported contents. Quality analysis was conducted using descriptive epidemiology methods. Results A total of 9548 cases were reported from 2005 to 2008 with 1291 duplicates. The annual average timeliness rates of report and verification were 67.60% (6454/9548) and 89.00% (8498/9548), respectively. The annual composite index was 8.10. A total of 64 logic errors were found. Of the reported cases, 30.37% were laboratory-confirmed, 64.20% were clinically diagnosed; suspected cases were 3.96% and 140 were pathogen carriers, accounting for 1.47%. The clinically diagnosed proportion constituted the majority of cases. Increasing number of reports, duplicates and timeliness of report and verification were shown over the years. Conclusion Despite improving comprehensive quality of reports in these years, reports of some chronic diseases, particularly HIV/AIDS, hepatitis and tuberculosis, affected the accuracy and sensitivity of infectious disease data to a great degree.