The invention discloses a rapid coupling agent for eliminating end surface roughness influence and improving testing effects of vertical and horizontal waves. The coupling agent is prepared into a powder material from materials such as gypsum, calcined gypsum, polyvinyl alcohol, white emulsion, potassium sulfate, sodium chloride, calcium oxide and magnesium chloride according to certain procedures, the powder material is stored in a sealing bag for later use, when being used, the powder material is mixed with water, the surface of a tested article is coated with the sufficiently mixed powder material, and an ultrasonic probe is also mounted for ultrasonic testing. The coupling agent is in a flowing molding state in an ultrasonic testing pretreatment procedure, a gap between the probe and the end surface of the tested article can be sufficiently filled, and the influence on the ultrasonic testing caused by the roughness of the end surface is eliminated. In ultrasonic wave testing, the coupling agent is in a hard molding state and has appropriate adhesion strength, so that the ultrasonic probe can be integrally adhered to the tested article, and then a relatively good vertical and horizontal wave testing effect can be obtained. In addition, the reaction mass of the materials can be calculated through chemical reaction equations, the coupling agent can be approximately neutral, and the corrosion of the tested article to the probe is alleviated.