Based on the DAlembert principle combined with NewtonEuler method and finite element method (FEM) were used in modelling of mechanical dynamics of the rolling hose head deployable mechanism. The FEM model was elastic mechanics model. On the contrary, NewtonEuler method was rigid model. The maximum axial force calculated by NewtonEuler method was 137 kN, while the maximum axial force calculated by FEM was 720 kN. The calculation results show that axial force curve of the hydraulic mast link frame calculated by FEM is smoother in changing, but with a large amount of calculation than that of calculated by NewtonEuler method. The phenomenon of waving distortion of the axial force curve was easily produced by the NewtonEuler method. NewtonEuler method and FEM models of mechanism design in prophase provide the scientific evidences for axial force value of cylinder of hydraulic mast link frame. It is helpful in design with superior performance of the hydraulic device of rolling hose head deployable mechanism.