The three-year-old pot-planted seedlings of Prunus cistenena cv. Pissardii were used to study the variation of leaf pigments, soluble sugar, activity of PAL, and coloration parameters under soil drought stress condition. The treatment design was control, slight drought stress, medium drought stress, and severe drought stress with relative soil water content of 18.11%, 14.72%, 11.32%, and 7.92%, respectively, which was artificially controlled by weighting. The results showed that the content of anthocyanin, flavonoids, chlorophyll, soluble sugar, activity of PAL, and “a*-value” were increased, and “L*-value” and “b*-value” were decreased under slight drought stress along with prolonged drought stress time. The content of main pigment, soluble sugar, activity of PAL, and “a*-value” were increased at first and then decreased, and “L*-value” and “b*-value” were decreased at first and then increased under medium and severe stress with prolonged drought stress time. The value of leaf coloration-emerging could be enhanced by short time drought stress, in which the key period of leaf coloration conversion was the 15th day under medium stress or the 12th day under severe stress. Anthocyanin was the key factor of leaf coloration-emerging in Prunus cistenena cv. Pissardii.