In order to solve the problem of difficult steering for the farm machinery chassis operation in hilly and mountainous area, a swinging steering chassis with flexible steering and small turning radius was designed. The chassis is composed of steering device, floating device, hydraulic system, engine, front axle, rear axle, control system, and PTO output, etc. The combination of water cooling system and CVT gasoline engine and hydraulic system can realize the power matching of the chassis. Through ANSYS Workbench, the mechanical model of the front bridge, rear bridge and overall mechanism of the wobble and steering chassis is built to analyze the variation trend of deformation parameters in different states of each mechanism, and optimize the vulnerable parts of the chassis mechanical mechanism that are prone to damage. The results show that accessories near the steering mechanism of the front bridge have a great influence on the deformation of the front bridge. The deformation amount of the front bridge structure using square steel with a thickness of 5 mm is 0.85 mm. After the optimization, the installed accessories of the front bridge adopt modular distribution, and the square steel with a thickness of over 10 mm is used to process and make the deformation amount of the front bridge stable control within 0.3-1.0 mm. The maximum equivalent stress of the rear axle of the chassis is 14 MPa, and the deformation is 0.25 mm, which decreased by 33.33% and 28.57% than that before optimization, respectively. The structural stability of the rack was improved. The pressure curve of the chassis in the driving process is stable and the pressure in the starting and stopping stages is within a controllable range through the testing of the physical platform by the pressure testing instrument. The driving straightness and off-course rate of the chassis are all less than 1%, and are not affected by the chassis load.