Abstract: In order to understand the differences of Aphis citricola in its original and final selectivity to the apple leaves with different leaf age, and to ascertain the effects of mature and young apple leaves on the growth and development, survival, and fecundity of A. citricola, this paper studied the host preference of A. citricola to mature and young apple leaves, with the related agestage twotype life tables constructed. A. citricola more preferred to oviposit on the young leaves. There existed differences in the behaviors between oriented selectivity and penetration selectivity, and the latter was the key factor determining whether A. citricola fed and oviposited on the host. The total development time of immature A. citricola on the mature leaves was significantly longer than that on the young leaves, and the survival rate was also lower, with the aphids died at the first and fourth instar stages and at mature stage. As compared with those on the young leaves, the apterae rate of A. citricola adults on the mature leaves was lower, and the longevity and fecundity were significantly shorter and lower. The population dynamic parameters suggested that the population growth of A. citricola was quicker on the young leaves than on the mature leaves, and it was difficult for A. citricola to establish a stable population on the mature leaves.