This paper deals with the biology of the Siamese algae-eater Abbotina rivularis (Basilewsky) in Panzhihua Reach, Jinshajiang River. Its production of the total catch was 7.68%; the average occurrence in the set gill nets was 93.1%. Body length ranged from 49 mm to 94 mat (mean=66.88 +/- 8.11 mm). There was a significant sex difference in lengths of these fish. The curve estimation between the body length and the body weight is W = 4 x 10(-5) L-2.8499 (R-2 = 0.8614). The analysis of age composition indicates 1.22% of the fish are less than I year old, 82.93% of the fish are I year old and 15.85% of the fish are 2 years old. The correlation between the scale radius and the body length is significant and the males have a stronger linear regression relationship than females. The reproductive period starts at the end of March. Absolute fecundity ranged from 737 to 4516 (eggs) with the mean value 1744 +/- 753 (eggs); and its relative fecundity ranged from 180 to 597 (eggs/body weight) with the mean value 295 +/- 87 (eggs/body weight). Egg diameters ranged from 0.28 mm to 1.24 mm, with a mean value 0.75 +/- 0.25 mm. The distribution has two peaks. Based on our observations we conclude that Abbotina rivularis is a single spawner.