Lake Ulungur is one of the most important fishery ground in Chinese inland area. To exploit the potential fishery resources, 15 species of fishes were introduced in the past 40 years. By far, most of the niches to the fishes endemic in Lake Ulungur were occupied by the introduced fishes. Perch(Perca fluviatilis Linnaeus) as the most economic important fish has endangered. The age structure and growth of perch population were studied in 2007-2008, and compared with the corresponding data in 1987-1989 to analyze the reason why population size decreased sharply. Body weight and length of captured perch were both smaller than those in 1987-1989 at each age except age 1⁺. The growth parameters using Von Bertalantty equations were L_∞=41.317cm, W_∞=15475.1g, k=0.1649, t₀=-0.2626;growth performance indices were Ф=2.4493. L_∞ and Ф reduced since 1987-1989 while k increased. However, the growth inflection point of body weight was the same as 1987-1989 (t=7). This investigation confirmed the remarkable effects of environment factors on perch growth and the effect mode of fish invasion on Perch(Perca fluviatilis Linnaeus) growth in Lake Ulungur were also revealed.