Based on 68 specimens collected from the northeast Chinese waters, the middle and lower reaches and mouth of the Changjiang River, the population biological characteristics of Neophocaena phocaenoides were analysed from the age, growth and reproduction angles. The relationship between age and growth follows the model of power function: Y = aX~b. Males attain the first sexual maturity at about 4.5 years and females at 4 years old. Mating may occur all of the year, and there may be two mating peaks during a year. The rough estimate of annual reproductive rate is 20%. Obviously, the populations of Changjiang River and northeast Chinese waters are different ecological populations. The present situations of Neophocaena phocaenoides were assessed. The conservation and management of Neophocaena phocaenoides and Lipotes vexillifer in the Changjiang River have been discussed.