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Hydraulic mechanical continuously variable transmission (HMCVT) is a transmission system combining mechanical and hydraulic power flow. The matching and design of the power source and transmission system contribute to the energy-saving and emission reduction of vehicles, and meet the requirements of modern society for environmental protection and energy-saving. This paper takes the transmission system of the pickup truck as a research object to research the transmission ratio control strategy of a self-designed new HMCVT with the goal of minimizing fuel consumption. The research compares it with the standard stepped automatic transmission (SAT). The vehicle model was based on CarSim and MATLAB/Simulink. The simulation was carried out under the EPA cycle, NEDC, and the six-mode cycle. The fuel consumption of SAT and that of HMCVT were compared. The results show that the average fuel savings of the pickup truck with HMCVT are 4.52% in the EPA cycle, 7.01% in the NEDC, and 4.84% in the six-mode cycle compared to the eight-speed SAT. In conclusion, HMCVT is more economically efficient than SAT.