A real-time data security method used for protecting the system data of a computer, wherein, the best embodiment sets up a file folder in the magnetic disk region of the original operating system which is loaded as a security segmented region to lead all the file data to visit the security segmented region, so as to achieve the goal of real-time encryption and decryption, wherein, the set of the security region is to set a file folder firstly, supplement a real-time encryption and decryption active X to the property of the file folder by using a real-time encryption and decryption module (likeOTFE), hide the file folder and load the file folder to the security segmented region. Besides, another embodiment can add a personal identification method to supplement a personal identification mechanism of the user. The data security method ensures the file system of the computer operating system to receive a file storing instruction when storing the files, executes a security program real-timely, annexes the encryption and decryption active X to the property of the file simultaneously and then executes the storing and processing work.