The invention relates to a preparation method for keemun black tea. The preparation method comprises the following steps: 1) picking fresh tea tree leaves with one bud and two leaves or one bud and three leaves of Camellia sinensis var. Sinensis cv. Zhuye; 2) withering: withering by a withering machine till the water content of the fresh tea leaves is 55-60%; 3) rolling; 4) dividing the whole fermentation process into two stages: the first stage is a high-temperature short-time fermentation stage, wherein the temperature is 30-35 DEG C, the time is 20-30 minutes and the relative humidity is over 95%; the second stage is a low-temperature long-time fermentation stage, wherein the temperature is 22-28 DEG C and the time is 120-150 minutes; and 5) drying. The preparation method provided by the invention solves the problem that the theaflavin of keemun black tea (middle/little leaf tea and Camellia sinensis var. Sinensis cv. Zhuye) is relatively low and the golden ring of the tea soup is not obvious.