Abstract Enhancing plasma injection efficiency and penetration depth is crucial for achieving high-performance steady-state fusion confinement in ITER, the next generation magnetic confinement fusion device. Based on the trans-neut module within the BOUT++ boundary plasma turbulence program framework, this study conducts two-dimensional simulations and comparative analyses of supersonic molecular beam injection (SMBI) on the high-field side (HFS) and the low-field side (LFS), using the actual divertor geometry of the HL-2A tokamak. The physical model encompasses plasma density, heat, and momentum transport equations, as well as neutral particle density and momentum transport equations. The results show that HFS SMBI produces deeper neutral penetration in normalized poloidal-flux space than LFS SMBI. The ion density inside the LCFS in the HFS case reaches about 1.5-2 times that in the LFS case, accompanied by a stronger reduction of the edge plasma temperature. The deeper HFS penetration is associated with the smaller local field-line slope on the HFS path, which causes a finite-width SMBI source to be mapped differently along the magnetic field compared with the LFS case. These results indicate that HFS SMBI can enhance both the penetration depth and the fueling efficiency in the present HL-2A geometry.