A hierarchical group key management approach based on linear geometry is disclosed. The approach includes the following steps: step 1, the central controller selects a finite field F, a mapping parameter f and a constant N for use in the group; the central controller selects a N-dimensional private vector for each subgroup; step 2, the central controller selects a mapping parameter r and maps the private vector to a new set of vectors in the vector space; step 3, the central controller selects a subgroup key for each subgroup and constructs n linear systems of equations, and solves the solution of the linear equation systems, that is, the public vector, and the n sets of public vectors form a public vector; the public vector and the mapping parameter r are broadcasted or multicasted by the central controller to all the subgroup controllers; step 4, each subgroup controller solves the confidential vector of its own, and a set of key vectors is obtained by linear transformation of the confidential vector and the public matrix. This invention is simple and flexible, and is effective against brute-force attacks.