One new kind of gas injection devices (GIDs), with moving-coil electromagnetic linear actuator (MCELA) and mushroom-type poppet valve, was projected to inject sufficient compressed natural gas (CNG) to a large-bore port fuel injection (PFI) engine. It had larger mass flow rate and better controllability than conventional GID. And the transient computational fluid dynamics (CFD) engine model incorporating the GID's motion was established to analyze the effects of the GID injection angle and poppet valve opening manner on the mixing homogeneity in the intake port, and finally, the in-cylinder mixing performance and gas movement intensity were compared. The results indicate that with the increasing of injection angle, the mixing homogeneity in the near-field injection location of intake port will be better, and the time when fuel starts to get into cylinder will be later. At ignition time, the injection angles 60 deg, 90 deg, and 120 deg show better in-cylinder mixing performance, while 150 deg has the worst. The pull-open GID injects more momentum to the intake port than the push-open one, and the mixing degree both in the intake port and cylinder is higher.