Methanol is considered to be an alternative fuel which saves crude oil. However, methanol-fueled engines have the technical problem of poor cold startability. An ultrasonic atomizer facilitates the atomization of methanol fuel under low-temperature conditions.This paper studies the effect of the methanol-gasoline blend ratio and flash boiling on spray evaporation characteristics when the ultrasonic atomizer is used. Spray plumes were observed with an image-converter-type high-speed camera at 10,000 frames per second. Fuel was sprayed under low atmospheric pressure at the boiling point of methanol.The experimental results of the spray observation show that the methanol-gasoline blend ratio affects the spray shape,especially the cone angle, because of the change of fuel evaporation characteristics. The methanol spray characteristics when an ultrasonic atomizer is used as shown in this paper are useful data for low temperature conditions also.