This study investigates artificial noise aided Multiuser Multiple-Input Single-Output (MU-MISO) broadcast wiretap system designs in slow fading channel environment. We adopt a beamforming technique with artificial noise to achieve secure multiuser communication and optimize system performance. To overcome the complexity of this model, a novel optimization scheme using semi-closed-form expressions and Monte Carlo method is employed to derive the relationship between transmission parameters and secure transmission performance. In this article, we detail the procedure of our new method, and conduct some heuristic simulation works. The simulation results reveal how power allocation ratio and information rate influence the multiuser system secure transmission probability and effective secrecy throughput of the multiuser system. We compare the multiuser system security and throughput performance with each user's performance, which helps us to verify the security ability of our method. Our research results extend the traditional single-user artificial noise design method to multi-user scenarios, and provide ideas for solving the optimization problem of multi-user broadcast communication.