Micro-Electro-Mechanic　System(MEMS)gyroscope　is　an　emerging　inertial　sensor.　On　account　of　fabrication　imperfections　and　field　application　of　MEMS　triaxial　gyroscope,the　complex　unmatched　perturbation　which　can＇t　be　regarded　as　equivalent　control　input　could　be　generated　and　cause　some　undesired　oscillations　in　MEMS　gyro,reducing　the　detection　accuracy　of　angular　rate.　Therefore,a　global　sliding　mode　controller　based　on　three-order　disturbance　observer(DOB)is　proposed　to　deal　with　the　effects　of　complex　unmatched　perturbation.　The　unmatched　perturbation　can　be　estimated　by　the　DOB　in　real-time,and　a　novel　nonlinear　sliding　mode　surface　is　proposed　to　achieve　global　robustness.　Finally,the　reachability　of　sliding　mode　surface　is　guaranteed　by　exponential　reaching　law.　Simulation　results　show　the　validity　and　effectiveness　of　the　three　order　disturbance　observer-based　global　sliding　mode　controller,the　estimation　error　of　unmatched　perturbation　decreases　from　0.58　to　0.18,and　the　position　response　performs　smaller　overshoot.　©　2020,　The　Editorial　Office　of　Chinese　Journal　of　Sensors　and　Actuators.　All　right　reserved.