Using microelectromechanical system（MEMS）technology，a Pt microheater fabricated on a glass wafer was placed in a silicon-based microchannel of trapezoidal cross section.With the aid of a high-speed charge coupled device（CCD）camera and based on Pt’s linear temperature-resistance characteristics，flow boiling phenomena and temperature response on the surface of the microheater in the microchannel under pulse heating were observed and recorded.At a given mass flux，two types of microscale boiling were observed with increasing imposed voltage，especially the growth of stable vapor film which rarely appeared in other similar researches.Finally，the corresponding microbubble dynamics and the differences during two neighbor pulse durations due to non-condensed gas were analyzed.