In　this　paper,　we　investigate　the　prob-lem　of　angle　of　arrival　(AOA)　tracking　for　the　large-scale　array　in　terahertz　(THz)　communication,　which　has　a　large　size　and　a　narrow　beam,　highly　demand-ing　an　accurate　angle　estimation.　On　the　one　hand,　the　system　usually　adopts　a　hybrid　structure　with　limited　radio-frequency　(RF)　chains,　which　increases　the　difficulty　of　angle　estimation;　on　the　other　hand,　the　rapid　mobility　of　users　also　brings　new　chal-lenges　to　angle　estimation.　To　address　the　above　challenges,　a　two-stage　tracking　framework　is　pro-posed　in　this　paper,　which　employs　the　random　phase　matrix　and　orthogonal　long　pilots　in　the　first　stage　to　reduce　the　complicated　multi-user　estimation　to　multiple　single-user　estimations,　followed　by　using　both　wide　and　narrow　beams　in　the　second　stage　to　serve　high-speed　and　low-speed　users.　Furthermore,　a　generalized-approximated-message-passing　(GAMP)　method　is　proposed　for　facilitating　a　low-accuracy　es-timation　of　the　angles,　followed　by　adopting　a　modi-fied　expectation-maximization　(EM)　algorithm　based　phase　estimation　to　unbiased　estimate　the　instanta-neous　angle　with　the　help　of　high-gain　characteristics　of　the　beams.　The　proposed　structure　can　not　only　simplify　the　estimation　complexity,　but　also　improve　the　estimation　accuracy　due　to　its　capability　of　trans-ferring　the　non-linear　problem　of　angle　observation　into　a　linear　gaussian　model.　In　addition,　the　Kalman　tracking　framework　is　employed　for　performing　a　con-tinuous　angle　tracking.　Numerical　results　show　that　the　angle　estimation　based　on　the　random　phase　ma-trix　in　the　initial　stage　can　obtain　a　high　enough　es-timation　accuracy,　while　the　GAMP　algorithm　imple-mented　in　the　second　stage　can　quickly　capture　the　an-gle　range　under　the　Rayleigh　limit.　The　performance　of　the　proposed　EM-based　tracking　method　is　shown　to　outperform　the　traditional　extended　Kalman　filter　(EKF)　method.