Abstract: Objective To understand the clinical and epidemiological characteristics of 4 confirmed cases of human infection with avian influenza A (H7N9) virus in Xiacheng district of Hangzhou, Zhejiang province, and provide evidence for the prevention and control of this kind of human infection. Methods All the confirmed cases and their close contacts were surveyed, and respiratory tract specimens were taken form the confirmed cases to detect the nucleic acid of H7N9 virus with real-time PCR. Results Four cases were diagnosed with severe and progressive pneumonia, The average interval between the onset of the disease and the first medical care seeking was 2 days, the average interval between the onset and the first hospitalization was 5 days and the average interval between the onset and the diagnosis was 7 days. The 4 cases were highly sporadic and no epidemiological links were found among them. All the cases occurred in spring and had the histories of farm produce market exposure, all the cases were isolated and treated, and all the close contacts received medical observation. Terminal disinfection was conducted and farm produce markets were closed. The epidemic was under control effectively. Conclusion The 4 cases of human infection with H7N9 were associated with farmer produce markets exposure, and no evidence of human to human transmission was found. Early detection and treatment of the cases infected with H7N9 are essential for the improvement of patients' prognosis, and it is necessary to strengthen the surveillance of H7N9 epidemic and conduct appropriate response to stop the spread of H7N9 virus.