The invention relates to a chassis system for a multifunctional vehicle. The chassis system comprises an automobile chassis part I and a sub-frame part II as a reinforcing part, wherein the sub-frame is provided with a horizontal part and a sinking part extending downwards from the horizontal part, and at least the horizontal part is connected onto a chassis. The sub-frame is used for installing a job operating part and an operating part assembly, and an operating component of the multifunctional vehicle is installed on the traditional vehicle chassis under the condition of unchanging the traditional vehicle chassis through the sub-frame.