An electrically heated microgroove vaporizer was proposed. The vaporizer mainly comprised an outer tube, an inner tube and an electrical heater cartridge. Microgrooves were fabricated on the extal surface of the inner tube by micro-cutting method,which formed the flow passage for fluid between the extal surface of the inner tube and the intal surface of the outer tube.Experiments related to the temperature rise response of water and the thermal conversion efficiency of vaporizer were done to estimate the influences of microgroove’s direction, feed flow rate and input voltage on the performances of the vaporizer. The results indicate that the microgroove’s direction dominates the vaporizer performance at a lower input voltage. The longitudina lmicrogroove vaporizer exhibits the best performances for the temperature rise response of water and thermal conversion efficiency of vaporizer. For a moderate input voltage, the microgroove’s direction and the feed flow rate of water together gov the vaporizer performances. The input voltage becomes the key influencing factor when the vaporizer works at a high input voltage, resulting in the similar performances of longitudinal, oblique and latitudinal microgroove vaporizers.