The invention discloses a device for quickly detecting leakage of a water cooler and a detection method. The device comprises a transparent chamber, wherein the left side and the right side of the transparent chamber are respectively provided with a water inlet and a water outlet at opposite positions, the transparent chamber is filled with an absorption chromophoric material, the water inlet is connected with a water inlet pipe, the water inlet pipe is sequentially provided with an inlet fast joint, a regulating valve, an inlet filtering screen and a chamber fast joint from front to back, thewater outlet is connected with a water outlet pipe, and the water outlet pipe is sequentially provided with an outlet filtering filler and an outlet fast joint from front to back. The detection principle is that if the color of a water sample discharged from the water outlet pipe is darker than the color of a water sample at the inlet, it is indicted that the water cooler leaks; and if the colorof the water sample discharged from the water outlet pipe is the same as the color of the water sample at the inlet, it is indicated that the water cooler is normal. The device can quickly judge a leakage condition of the water cooler by using a principle that the absorption chromophoric material performs macroscopic color development after absorbing a hydrocarbon phase, thereby performing the detection accurately and effectively.