Abstract: High-impedance surface of microwave photonic crystals substrate has been proven to be an effective way to reduce the surface wave excitation.This paper investigates the performance of a microstrip antenna phased array with high-impedance surface substrate.The results show that the use of high-impedance surface substrate can eliminate the scan blindness in a phased array.This paper presents a novel and efficient structure of high-impedance surface.A microstrip antenna phased array fed by coaxial line of 6×6 elements on a high dielectric constant substrate was designed and simulated.The simulation results show that high-impedance surface structure proposed in this paper can effectively improve the performance of the microstrip antenna phased array.