There are spatial differences in fish population structure and individual growth， which are affected by hydrology， water environment， and fishing. In order to study the population structure and growth differences of Megalobrama terminalis in the estuary， dam downstream， and dam upstream in the middle and lower reaches of the Pearl River， a total of 228 fish samples were collected in the middle and lower reaches of Pearl River from July to August in 2020. The body length and weight of the samples were measured， and the scales were used to determine the age. The von Bertalanffy growth equation， Beverton-holt model， and Pauly empirical formula were applied to estimate the growth and death parameters of M. terminalis. The results of comparative analysis showed that the dominant body length of M. terminalis was 17.0-27.2 cm in the Pearl River estuary， 18.9-28.7 cm in the dam downstream， and 28.6-40.0 cm in the dam upstream. The dominant body weight was 93.0-447.9 g in the Pearl River estuary， 148.8-480.0 g in the dam downstream， and 39.5-1 420.8 g in the dam upstream. The dominant ages were 3⁺ （32.14%） and 2⁺ （24.11%） in the Pearl River estuary， 3⁺ （32.14%） and 2⁺ （24.11%） in the dam downstream， and 4⁺ （31.58%） and 5⁺ （26.32%） in the dam upstream. The von Bertalanffy equation of M. terminalis was L=47.2 （1-e^{-0.177（t+0.387）}） in the Pearl River estuary， L=42.9 （1-e^{-0.199（t+0.377）}） in the dam downstream， and L=53.7 （1-e^{-0.155（t+0.401）}） in the dam upstream. The exploitation ratio （E） of M. terminalis was 0.410 in the Pearl River estuary， 0.373 in the dam downstream， and 0.248 in the dam upstream. The critical length （L_c） was 25.1 cm in the Pearl River estuary， 23.0 cm in the dam downstream， and 28.4 cm in the dam upstream. The results of comparative analysis showed that the frequency distribution of body length， body weight， age， and the growth equation of M. terminalis had spatial differences.