本文运用分形的基本定义及河系定律探讨了河长和河网结构的分维。海河水系河长的分维在1.01～1.14之间，河网的分维在1.50～1.69之间。

The application of fractal theory has been largely developed since it was used in geography and hydrology in 1980’s. In this paper, the fractal dimensions of stream length and river network are investigated by two methods of box counting and stream order law, and the fractal features of some main rivers in the Haihe River basin are practically estimated. The following conclusions were obtained through analysis. (1) It is feasible to study the fractal dimension of river morphology by two methods of box counting and stream order law. The accuracy of box counting is higher because the method uses the basic definition of fractal dimentsion, but its calculating work is very large, especailly for the fractal dimension of river network. The method of Horton’s stream order law can also provide the fractal imension by river system parameters. This indirctly shows that horton’s stream order law can reprent some basic characteristics of rivers. (2) The value of fractal dimension can be used as the index of river morphology becuase stream length and river network have the obvious fractal feature. The fractal dimension shows the complex of river morphology, and has the property of scale invariant. Therefore, the problem of calculation river morphology under different ratio scale can be resolved by the fractal dimension, and it is helpful to understand the evolution process of river morphology. (3) The fractal dimensions of stream length in Haihe River baisn vary from 1.01 to 1.14, and its mean value is 1.10. The fractal dimensions of Lanhe River and Daqing River are larger because their stream channels are zigzag. On the constrary, the fractal dimension of Rongding River is the smallest for its smooth stream channel. The fractal dimensions of river network vary from 1.50 to 1.69, and that of Zhiya River is the largest because it has many branch rivers. The mean fractal dimension of Haihe River system is 1.57, and this value accords with La Barbera and Rossos’s (1989) statistical data that the fractal dimensions of river network are from 1.6 to 1.7. This result shows that Haihe River system is roughly a standard river basin.