A method for permission management includes: generating a plurality of job roles with different permissions according to organization permission table; generating first permission structure directed graph according to the job roles; selecting one of the job roles in first permission structure directed graph as target job role; generating minimum directed spanning graph in first permission structure directed graph according to target job role; determining whether permission of each of the job roles in first permission structure directed graph matches job of each of the job roles in first permission structure directed graph; and adjusting permission and job of each of the job roles to generate second permission structure directed graph if it is determined that permission of each of the job roles in first permission structure directed graph does not match job of each of the job roles in first permission structure directed graph.