To address the problem of the flexible walking of bed chair robots in narrow indoor spaces, a four wheel independent drive steering bed chair integrated robot chassis is developed. Based on the steering requirements of indoor narrow spaces, the overall layout plan and main technical parameters of the chassis have been determined. Theoretical calculations and finite element analysis were conducted on important components, and stress and deformation analysis was conducted on the drive wheel bracket. The simulation results showed that the strength and stiffness of the drive wheel bracket met the design requirements. A dynamic simulation model of the chassis was established in ADAMS software, and stability analysis of forward tilt, backward tilt, and roll was conducted, as well as performance analysis of single side obstacle crossing and overall obstacle crossing. The simulation results showed that the various indicators of the chassis met the relevant national standards. The prototype experiment further validated the results of simulation analysis, confirming the stability, reliability, and steering performance of the bed chair integrated robot in narrow indoor spaces.