Humanoid　manipulator　motion　control　is　mainly　carried　out　by　trajectory　tracking　control.　As　the　largest　disturbance　of　a　spatial　manipulator,　gravity　force　is　necessarily　compensated　to　improve　the　control　precision　and　efficiency.　The　conventional　gravity　compensation　algorithm　requires　accurate　dynamic　parameters　and　complex　matrix　transformation　operation,　which　is　difficult　to　be　used　in　real　time　control.　Based　on　the　geometric　features　and　torque　balance　principle　of　spatial　manipulators,　this　paper　proposed　a　simple　and　practical　gravity　compensation　algorithm　that　does　not　need　complex　computation　of　coordinate　transformation　and　the　accurate　dynamic　models　and　parameters,　only　needs　the　largest　gravity　torque　estimation　of　manipulator　and　the　calculation　of　simple　trigonometric　function,　while　the　algorithm　is　also　suitable　for　non-parallel　axis　spatial　manipulators　with　N　joints.　To　verify　the　gravity　compensation　control　effect,　the　PD　controller　with　gravity　compensation　was　used　to　controll　the　manipulators　of　two　and　three　joints　based　on　simulation.　It　was　simulated　by　gravity　compensation　and　without　compensation　as　well　as　comparison　with　other　compensation　methods.　Results　show　that　the　gravity　compensation　algorithm　can　improve　the　trajectory　tracking　control　with　high　control　precision.　The　compenstion　method　can　effectively　reduce　the　work　burden　of　a　controller　and　improve　the　stability　of　the　system.　The　compensation　effect　is　satisfactory.　©　2019,　Editorial　Department　of　Journal　of　Beijing　University　of　Technology.　All　right　reserved.