Static security region (SSR) plays a crucially important role in power system monitoring and operation. Boundaries of SSR are usually obtained through continuation power flow (CPF) calculation. Considering the effects of generation regulation, this paper improves the CPF for boundary computation of SSR in two aspects: 1) a general method of handling the effects of active power and reactive power limits is provided so that the CPF results are independent of slack bus selection; 2) a general interface for CPF to incorporate generation regulation is proposed. This improved CPF for boundary computation of SSR when considering generation regulation is realized and then tested on IEEE-14 and IEEE-118 systems. Test results show the effectiveness and efficiency of the proposed algorithm.