This paper proposes an adaptive PEH interface circuit based on triple steps bias-flip strategy in 0.18-µm CMOS technology. Aiming at the problem of piezoelectric sensor and external flip inductance change, adaptive time control circuit is put forward in this paper, achieving adaptive control of the bias-flip switch sequence and improving the efficiency of EH while avoiding external adjustment. Moreover, the whole circuit modules are powered by storage capacitance Cs and the S3BF interface circuit has the cold start-up capability. The energy extraction efficiency has been improved by 3.7 times compared to FBR.