Aiming　at　balancing　control　of　the　cubical　robot　on　its　corner,　a　balance　control　method　is　introduced　based　on　the　sliding　mode　control(SMC)　in　this　paper.　The　dynamic　model　of　the　cubical　robot　is　derived　with　Lagrangian　method　according　the　manufactured　prototype.　A　balancing　controller　is　designed　and　implemented　for　the　cubical　robot　balancing　on　its　corner　base　on　a　nonlinear　control　method　-　sliding　mode　control.　A　series　of　experiments　are　conducted　by　simulation　and　comparative　analysis　between　SMC　and　PID　controller　is　made.　Numerical　simulation　results　show　that　the　SMC　not　only　can　control　the　balancing　of　the　cubical　robot　effectively,　but　also　with　superior　performance　in　fast　response　to　reference　changes　and　strong　robustness　to　PM　controller.