Methanol fuel, as a low-carbon alternative energy source, its combustion and physical properties have a significant impact on the engine valve system. The valve mechanism needs to adapt to the changes in the requirements for charging and combustion. This paper mainly analyzes the physical and chemical properties of methanol fuel, and studies the requirements for the valve mechanism based on the working principle of methanol engines. Focusing on the design of the valve mechanism for low-carbon methanol fuel engines for automotive power systems, the article proposes four selection methods: adjustment of intake process parameters, adjustment of exhaust process characteristics, design of valve movement laws, and selection of valve mechanism materials. Combined with engineering applications, the design effect is verified, aiming to enhance the working condition adaptability and application level of methanol engines.