The invention discloses an instant high-temperature wetting area observation test device. The device comprises a sealing box, cooling grooves, an electric heating furnace and a transmission rod; an air inlet is formed in the top of a box body of the sealing box, an air outlet is formed in the bottom of the box body of the sealing box, the cooling grooves are formed in the bottom inside the sealing box, an electric heating furnace is assembled above the cooling grooves through a supporting frame, a carrying platform is arranged in the electric heating furnace, one end of the transmission rod is connected to the carrying platform, and the other end of the transmission rod penetrates the top of the sealing box and is connected to stepping motors; the size of the instant wetting area of brazing materials heated to a certain temperature can be measured, the influence of spreadability along with the temperature and heat preservation time in the brazing material wetting and spreading process can be observed, and the device is ingenious in design and convenient to popularize.