The low-cycle fatigue test and the simulation evaluation were conducted to evaluate the low-cycle fatigue life based on the cylinder head of a diesel engine. In the experimental study, the pre-tightening state of cylinder head was close to the actual state of matching engine by considering the bolt pre-tightening load and stiffness matching calculation. Two thousand times low-cycle fatigue tests of cylinder head were carried out on the gas thermal load test bench and the thermal cracks were not found after flaw detection. In the simulation analysis study, the low-cycle fatigue life at the examination point of the fire surface of cylinder head was calculated based on the sub-model analysis technology and the plastic strain energy theory. The analysis results showed that the position of the lowest cycle life was located in the exhaust bridge zone with the life of 2 863 times. The test and simulation results showed that the cylinder head met the design requirements of low-cycle fatigue life greater than or equal to 2 000 times. Finally, the rationality of experimental method and the accuracy of finite element analysis of cylinder head for lowcycle fatigue were verified.