An aperture-coupled full polarization reconfigurable MIMO antenna is proposed in this letter. A cross-shaped slot loaded with PIN diodes is embedded on the ground plane, and ±45° linear polarization is realized by controlling the states of the diodes. Four slots integrated with PIN diodes are etched at the corners of the radiating patch, and then the left- and right-handed circular polarization modes are achieved by changing the ON/OFF states of the diodes. Experimental results show that the antenna can achieve good impedance matching in the range of 2.4-2.46 GHz in four modes with an isolation greater than 15 dB and an axial ratio less than -3 dB in the circular polarization modes.