The simulation study was carried out on a turbocharged direct injection gasoline engine with a passive pre-chamber. The three-dimensional simulation model of pre-chamber ignition engine was established, and the lean-burn combustion environment (excess air coefficient λ=1.3) was formed by using the three injection strategy. The gas flow, spray, combustion and emission characteristics at different working conditions were studied by simulation. The simulation results show that a significant tumble flow of intake air is formed in the main chamber, and the maximum turbulence kinetic energy (TKE) at the end of combustion can exceed 150 m²/s², but further delaying the ignition time to 715° crank angle, the maximum TKE will drop to about 110 m²/s². During the jet flame spraying process, there is a significant imbalance, with the jet flame spreading faster from the right-side nozzles, while the jet flame spreading slower in individual left-side nozzles. By delaying the ignition time under heavy load, the maximum temperatures of the main chamber and the pre-chamber are effectively reduced, thus reducing the maximum pressure and emissions of NO_x and CO. The maximum mass concentration of NO_x in the main chamber is reduced by about 54%, and the maximum mass fraction of CO is reduced by about 30%.