In multiple-input-multiple-output (MIMO) wireless communications, Space Shift Keying (SSK), Spatial modulation (SM) and Generalized Space Shift Keying (GSSK) are three novel MIMO modulation techniques, that can greatly reduce the complexity of MIMO systems. This paper investigates the physical-layer security in typical MIMO systems of these three modulations. We present an exhaustive analysis of secrecy rate for multiple antennas destination and eavesdroppers receivers. Without eavesdroppers channel information, both achievable secrecy rate and bit error rate (BER) are studied through joint modulated signal and jamming signal transmission. Our simulation results demonstrate that the proposed proactive source jamming method achieves improvement of secrecy rate and improved BER performance for multi-antenna users.