Abstract: Based on Reynolds time-averaged equation and Realizable k-ε turbulent model, the internal dynamics and operating performance of an OB-84 axial flow fan with rear guide vane were numerically simulated in full flow passage by considering the effect of abnormal installation angle of single blade. Results show that the total pressure and efficiency tend to decrease with the rise of installation angle deviation Δβ, and the effect of cocurrent deviation is generally more remarkable than that of countercurrent deviation. The deviation of installation angle may cause deformation of total pressure and acoustic distribution, and with the rise of Δβ, the deformed region may be expanded from the lower pressure and higher noise region in circumferentially adjacent flow passage to the lower pressure and higher noise strips covering the circumferential downstream multi-passages. With the increase of flowrate, the influence of installation angle deviation is different on the internal dynamics and operating performance of axial flow fan.