Based on terahertz time domain spectral (THz-TDS) system, we use two mutually perpendicular photoconductive antennas construct a 1×2 GaAs photoconductive terahertz source array. Its radiation terahertz wave polarization direction is studied by adjusting the bias voltage of each array element. The results indicate that, on the basis of the efficient synthesis of photoconductive emission antenna arrays and the detection antenna that can simultaneously detect the amplitude, phase and polarization state of pulsed terahertz waves, the intensity of terahertz waves radiated by two parallel and vertical elements are changed by adjusting the bias voltage of each array element. After 1×2 GaAs photoconductive terahertz source array synchronously synthesized in the far field, pulse terahertz waves with different polarization directions are generated, realizing a photoconductive terahertz radiation source that can generate terahertz waves with arbitrary polarization direction in a fully electrically controlled manner.