In high switching frequency applications, for the purpose of the high efficiency and low electromagnetic interference (EMI), an adaptive soft switching technique is proposed in this paper. According to the resonance characteristics of system, a valley point detection circuit is designed. Besides, considering the driving delay of power MOSFET, an adaptive control circuit is proposed to generate a flag signal of driver, by which the adaptive zero voltage switching can be achieved. With the help of proposed adaptive zero voltage switching, the precise zero voltage switching independent of driving delay and type of power MOSFET can be automatically realized. An adaptive zero voltage switching control circuit is implemented in a 0.35μm BCD process. It allows high efficiency and low EMI, as well as good thermal performance.