This paper proposes a high speed inter rogation method for the dynamic and static strain gauge using the time synchronicity of multi-reflection spectrum from superimposed fiber Bra gg gratings (FBGs).The superimposed FBGs can provide equidistant space of generated sensing pulse train in time domain during dynamic strain gauge,when a triangular scanning voltage is applied to the tunable filter .Both the interrogation speed and accuracy are improved by combining centroid finding with smooth filtering method s.The interrogation speed of dynamic strain has been enhanced by four times by generating a 2kHz optical sensing pulse train from a 500Hz scanning frequency.The interrogation uncertainty and total harmonic distorti on (THD) characterization of superimposed FBGs are tested,and less than 4pm standard deviation is obtained.