The analysis of the point defects is an important method to solve the problem.Typical point defects distinguished as pinholes or bumps in automobile sheet coating were investigated in the present study.Cross-sectional images of pinholes in prime coating or top coating show that they were caused in the same way by fractures in base steel or a zinc alloyed layer.Furthermore,the formation of the defects is inferred,along with the specific painting process.The analysis also shows that bumps frequently occurred in the e-coating layer were mainly caused by contamination. The analysis of the point defects is an important method to solve the problem .ypical point defects distinguished as pinholes or bumps in automobile sheet coating were investigated in the present study. Cross-section images of pinholes in prime coating or top coating show that they were caused in the same way by fractures in base steel or a zinc alloyed layer .Furthermore, the formation of the defects is inferred, along with the specific painting process. The analysis also shows that bumps are occurred frequently in the e-coating layer were due caused by contamination.