The strongly weathered rock zone is a special kind of rocks and soils mass. For its larger burial depth and low utilization of natural foundation, the physical and mechanical properties of the strongly weathered diorite were grasped poorly. In the article, the normal investigation together with test in-situ has been applied in the project. The physical and mechanical properties of the strongly weathered diorite were analyzed deeply by the methods of field exploration, laboratory test and testing in-situ. It is feasible for the intensively weathered diorite to serve as natural foundation after lucubrate research and the evaluation of bearing capacity and settlement deformation in the project of the office building of China Industrial and Commercial Bank, Shandong Branch..It is proved from practice that the item of foundation treatment saved about two million Yuan compared with the pile foundation. Moreover it speeded up the process of the construction enormously, lessened the difficulty of the construction and obtained tremendous economic and social benefits.