The thermodynamic design and calculation were carried out to a certain reciprocating compressor under the variable condition requirements; the comprehensive piston force curves were drawn and the maximum stress and the corresponding position of the crankshaft were obtained under two operating conditions by meshing the crankshaft and introducing its crankshaft model into ANSYS Workbench software; moreover, the stress distribution, deformation and static strength of the crankshaft were analyzed. The results indicate that the compressor may conform to the design requirements under changing operating conditions and the static strength of the crankshaft may meet the operating requirements; at the same time, a certain basis may be provided to the thermodynamic design and crankshaft strength analysis of the same type compressors.