An active electromagnetically induced transparency (EIT) metamaterial is designed based on photosensitive gallium arsenide. The photoelectric characteristics of gallium arsenide make the peripheral circular closed loop (PCCL) in a metamaterial structure respond to electromagnetic waves with different frequencies under different illumination conditions. It is coupled with its central split ring resonators (CSRRs) and thus a strong EIT effect is produced at two frequencies of 0.7 THz and 1.5 THz. The conductivity of gallium arsenide is changed by adjustment of light intensity, and the structures of surface metal rings are dismantled and compared. The photosensitivity of this metamaterial structure and the physical mechanism for the realization of a multiband EIT are analyzed. At the same time, the influences of gallium arsenide width, CSRRs opening size and substrate thickness on EIT are investigated. The simulation results show that this metamaterial structure can be used to achieve a strong hysteresis effect at multiple frequency points and simultaneously a relatively high refractive index sensitivity in the terahertz frequency range under different illumination conditions. It has certain application value in the fields of terahertz buffer devices and refractive index sensing.