This invention relates to a method for improving the OS security through the incompatibility of process acts, and the major steps is as followed: 1.1) defining a group of key acts which is possible to have the incompatibility such as mutually exclusion, 1.2) each process has the rules of incompatibility in a certain way of recording, 1.3) each process records the occurred key acts according to a certain form, 1.4) the key acts must be checked for taboo before occurrence, and judgment is make according to the rules of incompatibility and the occurred key acts. If there is incompatibility in the occurred key acts, such as the mutually-exclusive acts have been occurred , the key acts is regard as the taboo behavior and not permitted its occurrence. The beneficial effect of the invention is that: incompatibility of process acts is introduced into the computer operating system, and according to the process, the occurred acts control the follow-up to improve the security of computer system. |