This course introduces postgraduates and senior undergraduates to theory and advanced techniques in quantum mechanics. It basically covers the following contents: (1) the correspondence between quantum mechanics and classical mechanics; (2) phase and gauge transformation in quantum mechanics; (3) path integral representation of quantum mechanics; (4) symmetry and conservation laws; (5) theory of angular momentum; (6) interaction picture and perturbation; (7) quantum scattering theory etc. The actual contents of this course could be slightly modified.