Due to the limitation of non-road vehicles' structure and cost, a structure of four-cylinder diesel engine crankshaft with rigidly coupling CVT was proposed. Characteristics and working principles of the new structure were presented. Calculation models were established separately for rotational vibration analysis of the newly proposed structure and the crankshaft with clutch. By carrying out the crankshaft front-end experiment, the presented model and the calculation method were validated. After solving both models for torsional vibration characteristics and parameters, results were compared. The comparison indicates that crankshaft with rigidly coupling CVT make the vibration fluctuation and the crankshaft dissipation power increase while the corresponding speed of resonance peak value decreases. The impacts on crank shear stress turn out to be small, while the shear stress tends to decrease at low speed condition and increase at high speed condition. Also, the torsional vibration amplitudes and shear stress at the end of CVT are larger. Through the comprehensive comparison, it can be concluded that the crankshaft with rigidly coupling CVT can be adopted on non-road low-speed four-cylinder diesel engine.