The LNG cylinder frame is one of the most important components of the LNG fuel device on heavy trucks. Under emergency braking, sharp turning, and actual road impact loads, the cylinder frame is vulnerable to static strength damage and fatigue damage caused by insufficient fatigue strength, which affects the safe operation of heavy trucks. Hypermesh is used to process the grid, Nastran is used to conduct static strength analysis, and Ncode is used to conduct fatigue analysis. The maximum stress value, maximum displacement value, fatigue damage value, and other data of the cylinder frame under different working conditions are obtained. The safety and structural weaknesses of the cylinder frame are analyzed, and an improvement scheme is proposed and verified through finite element analysis. The results show that the static strength safety factor of the improved cylinder frame is increased by 113%, and the maximum fatigue damage values at 8000 km and 16000 km are decreased by 53.5% and 27.9%, respectively.