In this paper, an improved clamped-HERIC topology based on GaN devices is proposed to address the common mode leakage current problem of non-isolated photovoltaic inverters. Working states of the proposed topology are analyzed in this paper and its functionality is verified by simulation. A 5kW prototype has been designed for the proposed improved clamped-HERIC topology ， which is expected to achieve 98.6% full load efficiency and 98.9% peak efficiency.