The simulation model of a boosting CNG engine was established and the accuracy of the model was verified. The camless intake profile with an intake late closing angle of zero degree was designed and the throttle was fully open. Then the effects of camless intake profile on engine intake performance were simulated and analyzed at 1 600 r/min with the intake manifold pressure of 120 kPa. The results show that camless intake profile can avoid intake backflow effectively when the intake valve closes at BDC. Meanwhile, the volumetric efficiency increases by 1.7%, the indicated power increases by 1.29% and the brake specific fuel consumption decrease by 2.88% after using the camless intake profile. According to the slicing of intake process and incylinder velocity field and 1D simulation data, the intake mass per cycle increases by 1.45% and it is more beneficial. In addition, the optimal intake closing angle corresponding to the camless intake profile also increases with the increase of intake pressure and engine speed.