Aiming　at　the　tracked　vehicle　with　coupled　pump-motor　hydraulic　steering　system,　the　vehicle　system　coupling　model　based　on　MATLAB/Simulink　was　established　under　the　braking,　steering　and　straight　driving　scenario.　The　mathematical　model　of　hydraulic　steering　regulation　system　with　variable　pump　and　quantitative　motor　is　established.　After　analyzing　the　kinematics　and　dynamics　of　the　tracked　vehicle,　the　vehicle　system　coupling　model　under　the　above　working　scenario　was　established.　The　main　performance　parameters　of　the　vehicle,　such　as　track　speed,　steering　radius,　steering　driving　force　and　steering　high　pressure,　are　studied　under　the　conditions　of　different　variable　pump　swash　plate　inclination　angle　(different　pump　displacement),　different　vehicle　braking　force　and　different　engine　speed.　The　stability　of　the　combined　pump-motor　hydraulic　steering　system　is　evaluated,　and　the　correctness　of　the　established　model　is　verified,　which　has　certain　theoretical　guiding　significance　for　the　research　of　the　steering　control　strategy　of　tracked　vehicles.　©　COPYRIGHT　SPIE.　Downloading　of　the　abstract　is　permitted　for　personal　use　only.