It is easy to ignore the impact of stray capacitance on the converter during the design process of an LLC converter. In this paper, the impact of stray capacitance on the working principle of LLC converter is analyzed on the basis of the developing mechanism of stray capacitance. The existence of stray capacitance not only affects the soft-switch process of primary switch, but also distorts the output voltage gain under light or no load. Based on the optimization of dead time and compared with the existing solutions to the problem of gain distortion, a novel dual hysteresis adaptive Burst digital control scheme is proposed to improve the conversion efficiency under light load while stabilizing the converter output voltage. Finally, the correctness and feasibility of the proposed control scheme were verified by tests on an experimental prototype.