Abstract: The coupling gap between traditional open-loop microstrip resonators of high temperature superconductivity filter is too narrow to be fabricated with normal photolithography technology. This paper studies the mixed coupling of high temperature superconductivity open-loop microstrip resonators and presents a new improved resonator structure which can be fabricated with normal photolithography technology. A six-pole high temperature superconductivity linear phase filter is designed with this new structure and simulated results are also presented here.