To enhance the field adaptability and stability of agricultural robot chassis, a four-wheel independent drive steering chassis was specifically designed for acquiring wheat phenotypic information in Shandong Province. Taking into account the agricultural requirements for wheat cultivation and the driving terrain conditions, comprehensive layout plans and main technical parameters of the chassis were determined. The design focused on the drive components, steering components, and swing arm balance components of the chassis, followed by parameter verification and component selection. An ANSYS finite element model was constructed to analyze stress deformation in the swing arm balance mechanism and simulate the vibration modes of the frame. The simulation results indicated that the swing arm balance mechanism exhibited sufficient strength and stiffness to meet the design requirements, while the frame effectively mitigated resonance caused by terrain excitation. Furthermore, an ADAMS dynamic simulation model of the chassis was established to conduct longitudinal and lateral stability analysis and assess the chassis ability to traverse single side protrusions and dents. The simulation outcomes demonstrated that both the transverse and longitudinal stability of the chassis met the design criteria, and the swing arm balance mechanism effectively compensated for changes in centroid height caused by unilateral obstacles, thereby enhancing driving stability. Field experiments confirmed the excellent driving performance of the robot chassis, with an average deviation rate of 0.51% on hard ground during straight driving and 1.13% on field terrain. The center point offset for turning in place was measured as 3.1mm, and the minimum turning radius for Ackermann turning was determined to be 1.125mm. Additionally, the longitudinal tilt angle reached 34°, while the lateral tilt angle reached 28°. It was noteworthy that the maximum height for traversing unilateral obstacles and the maximum depth for crossing unilateral pits were both 160mm.