The vast majority of automotive frontal crashes take place with 30% to 70% partial overlap of vehicles. In this paper a light-bus refitted from truck chassis is analyzed and a finite element model emphasizing the frame is set up.Offset frontal impact is studied using ANSYS/LS-DYNA3D. Through statistics from several simulation results(overlap 25%,35%,50%,75%,100%) the relationship between deformation and overlap ratio is established. Plastic energy-absorbing model in full-size frontal impact is extended to offset frontal one. The energy distribution vs.collision width under offset impact is subjected to hyperbolic one.