In this study, the auto-releasing mechanisms of tipper trucks are designed and simulated. There are two plans of auto-releasing mechanisms based on these theory geometries working principle with Model A is generally used in industry, and Model B is used for theory materials studying. And the result shows that the two plans have different compositions, mass, and operating principles. Therefore, the authors conduct a dynamic analysis to show standard moment needed for opening the locker of Model B is dominated by Model A. Finally, two plans of auto-releasing mechanism have 2 sides to them. After designing models, calculating, and simulating in the software that proved the working principle and general theory geometry for analyzing operation states, we concluded that Model A is more commonly used than Model B for proper operation and safety reasons.