Abstract: ObjectiveTo investigate the prevalence and gene characteristics of different groups of human parainfluenza virus (HPIV) infection in hospitalized adults with acute respiratory tract infections (ARI). MethodsRT-PCR was used to detect HPIV hemagglutinin (HA) DNA, which was extracted from sputum samples of 1 039 adult patients with ARI from March, 2014 to June, 2016. The HA gene amplified from randomly selected positive samples were sequenced to analyze the homology and variation. Results10.6% (110/1 039) of these samples were positive for HPIV, including 8 cases of HPIV-1, 22 cases of HPIV-2, 46 cases of HPIV-3 and 34 cases of HPIV-4. Detectable rate varied among different groups of HPIV according to seasons of the year and ages of patients. No significant differences were found between the positive samples and the reference sequences. Compared with different reference strains of different regions, the genetic distance of nucleotide is the smallest between the strains tested in this study and the reference strains of other provinces and cities in China. ConclusionIn Chengdu region, HPIV virus is highly detected in ARI, all subtypes were detected with HPIV-3 being the main subtype.