The invention discloses a Hami melon essence for a cold drink as well as a preparation method and application thereof. The preparation method comprises the following steps: preparing a Hami melon flavour base by virtue of a flavour blending technology; then preparing a vegetable oil treatment solution through an enzymatic hydrolysis reaction, wherein vegetable oil takes coconut oil and palm oil as raw materials with a mass ratio of 1:(0.5 to 1), the adding amount of lipases is 1-3%, the mass ratio of the vegetable oil to water is 1:(3 to 5), the temperature is 35-45 DEG C, the pH value is 7.5-8, the ultrasonic intensity is 2-3W/cm<2>, and the reaction time is 40-60min; then matching the Hami melon flavour base with the vegetable oil treatment solution to prepare the Hami melon essence for the cold drink, wherein the dosage of the vegetable oil treatment solution is 1-5%; and finally applying the Hami melon essence to the cold drink. The Hami melon essence is low in dosage and cost, capable of generating an obvious flavouring effect, good in entrance fragrance diffusivity, mellow and full, capable of increasing oral cavity rich texture, and lasting in remaining taste.