It is stated in the paper that deep excavation has such features as incomplete basic theory, integration of comprehensiveness and specialty and high cost sensitivity and that the risks in deep excavation has such features as integration of system property and stage property, integration of absoluteness and relativity and integration of incidental property and inevitability. Regarding the common risks in deep excavation, systematic risk prevention and control methods are proposed. Regarding the weak points in the technological system of deep excavation, such as quality control of diaphragm walls, risk perception in the excavation stage and control of hazards induced by artesian water, countermeasures, including optimization of the slurry management and the joint technology, control of the quality of the bracing by using "bracing compression" parameter and control of ground surface settlement induced by artesian water pumping by means of integration of water pumping and water injection, are proposed. 