In this paper, the L-shaped slot antenna is designed for Load-modulated Beamspace-MIMO system. The proposed antenna is composed of four L-shaped slot antennas structure. Each antenna radiates to different directions for low correlation with other antennas. We designed the general Load-modulated Beamspace-MIMO single RF system for testing successful BPSK signal transceiving. The transmitter is composed of BPSK impedance loading board and L-shaped slot antenna. The receiver consists of 2.375GHz dipole antenna and spectrum analyzer. In this test, the currents of proposed antenna are controlled by BPSK impedance loading board. Because the proposed antennas could transmit the BPSK signals without interference, the dipole antenna could receive BPSK signals successfully in constellation.