The　wide　application　of　large　inertia　loads　in　space　drive　mechanisms　is　relatively　rare　in　theoretical　research.　An　8-degree-of-freedom　nonlinear　dynamic　model　is　established　for　the　time-varying　and　nonlinear　perturbation　problems　of　a　large　inertia　load　space　drive　mechanism.　The　model　is　a　two-stage　spur　gear　model　in　which　the　effects　of　backlash　and　time-varying　stiffness　are　considered.　The　3D　model　was　imported　into　ADAMS,　and　the　nonlinear　dynamic　response　of　the　system　was　studied　by　motion　simulation.　This　paper　sets　up　a　large　inertia　experimental　device　to　collect　and　process　data.　Comparing　experimental　results　with　Adams　results,　the　correctness　of　the　numerical　model　was　verified,　and　the　reasons　for　the　differences　between　the　two　were　explained.　A　comparative　analysis　of　the　load　response　under　different　inertia　was　performed　to　illustrate　the　importance　of　studying　large　inertia　loads.　The　simulation　results　show　that　the　output　shaft　has　a　great　influence　on　the　dynamic　response.　Changing　the　material　of　the　gear　can　improve　the　transmission　precision　of　the　gear　system.　The　analysis　results　in　this　paper　enrich　the　research　on　the　dynamic　response　of　gear　system,　and　provide　a　theoretical　basis　for　the　subsequent　design　of　large　inertia　load　gear　system　and　improve　vibration　and　noise　during　operation.　©　2020　Chao　Li,　et　al.