To make a study of Truck System of Pump,a multi fields coupling dynamic model concerning the mechanical,hydraulic of the mobile Truck System is established using Mworks platform based on the Modelica language. On the basis of the mechanical and hydraulic coupling modeling, a precise model of PD control on the hoisting amplitude and speed is proposed and control program is developed. The luffing working process of the Truck system is simulated and the luffing force curve over time is obtained in the hydrocylinder.The results show that the established coupling model of machine.fluid and control matches well with the practical situation and are of significant practical value to the multi domain coupling modeling of the Truck System of Pump mechanism.