A method and a computer system for data sharing between multiple applications running on a mobile device are provided. The method comprising: receiving from a second application among the multiple applications an access request to first data in a first application among the multiple applications; in response to the access request, enabling the second application to access the first data via a sharing zone between the first application and the second application; and wherein the sharing zone is built by obtaining an access right over the first data, obtaining an access policy assigned by the first application to the second application for access to the first data, and building the sharing zone according to the access policy by using the access right. By means of the method and the computer system of the present invention, data can be shared between various applications running on a mobile device without changing developed applications.