In this letter, a new security enhancement scheme for space shift keying (SSK) systems under imperfect channel state information (CSI) is proposed. In this scheme, the legitimate receiver is always accompanied by an eavesdropper, and the secrecy enhancing of the SSK system is realized by adding the designed artificial noise (AN). Since the AN is designed by the CSI of the legitimate channel, it can be canceled at the legitimate receiver and remained at the eavesdropper. In addition, the impacts of the CSI estimation error on the secrecy rate (SR) and bit error ratio (BER) of the SSK system have also been taken into account. The simulation results show that compared with the traditional SSK under imperfect CSI environment, the proposed scheme improves the SR and BER. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.