A fast calculation code for 3-D unsteady inlet distortion was developed for solving 3-D Euler equations with body force.The 3-D unsteady numerical simulation of circumferential fan/compressor with inlet distortion can be achieved through the code.The characteristics of fan with inlet steady total pressure distortion in an aeroengine were simulated and compared with experimental results.It demonstrates that 3-D unsteady inlet distortion of circumferential fan can be simulated by the code with less computer resources.The effects of inlet distortion on fan/compressor can also be simulated accurately.