This study provides the biology of the population of Periophthalmodon septemradiatus, as a basis for species conservation. The result analysis of 3,436 individuals collected on a monthly basis starting from July 2017 to June 2019. Five sites including Long Duc, Long Phu, Soc Trang (LD), An Lac Tay, Ke Sach, Soc Trang (ALT), Phu Thu, Cai Rang, Can Tho (PT), Tan Hung, Thot Not, Can Tho (TH), and Binh Duc, Long Xuyen, An Giang (BD) were conducted along the Hau River from the estuary to the upstream of the river. It showed that the male to female ratio ranged from 1.36:1.00 to 1.87:1.00. Although this species' L∞ was 12.6 cm for all five populations, the growth coefficient (K) and t0 varied with studied sites. The K value ranged from 0.49 yr-1 (PT) to 1.6 yr-1 (BD), whereas the t0 was -0.12 in BD and -0.43 in PT. Likewise, the longevity of this species was the lowest value in BD (1.88 yr.) and the highest one in PT (6.12 yr.). The total mortality and natural mortality coefficients of fish populations displayed the highest values in the BD (Z=4.11, M=3.14) and the lowest one in PT (Z=1.68, M=1.46). Conversely, the highest and lowest values of the fishing mortalities (F) were in TH (1.58) and PT (0.22), respectively. The species populations were subjected to overfishing in ALT and TH.