Studies on the relationship between roots and soil are important to determine fundamental reasons for ecological degradation of riverside belt areas. Concentrating on the problem of ecosystem degradation in the Lijiang River, this paper explored the plant's root distribution features in degraded ecosystems of the river-land ecotone. In the repair process, characteristics of the root distribution are an important basis for the characterization of different herbs' soil and water protection functions. Thus, there is an urgent need to carry out studies on the distribution of dominant types of herbaceous plant roots at different sites of the Lijiang River ecotone. This paper studied the root length density at different soil depths and assessed the correlation between root characteristics and soil organic matter, total nitrogen, and available phosphorus. The results show significant difference between specific root lengths within each shrub community and each soil layer. The root length density decreased from Pterocarya stenoptera to Geum aleppicum to Securinega suffruticosa. In soil layers at 0-10 cm and 10-20 cm depth, the root length density decreased for each shrub community, but the decrease was gradual, indicating that the effects of the terrain surface, types of plants, and growth conditions on the distribution of root length density gradually decrease with the increase in soil depth. Pterocarya stenoptera had high total nitrogen content and root length density 1.24-fold that of Geum aleppicum and 1.87-fold that of Securinega suffruticosa. The difference in total nitrogen content significantly decreased from Pterocarya stenoptera to Geum aleppicum to Securinega suffruticosa. The available phosphorus content decreased from 11.56 g/kg in Securinega suffruticosa to 5.37 g/kg in Geum aleppicum and 3.99 g/kg in Pterocarya stenoptera. Since the Lijiang River water has been affected by human activities for a long time, the available phosphorus content is much greater in Securinega suffruticosa than in other species. The root length density is positively correlated with organic matter and total nitrogen and negatively correlated with the available phosphorus. We can, therefore, conclude that with more soil roots, there is more organic matter and total nitrogen and less available phosphorus. Root length density is significantly positively correlated with root diameter in the class of less than 1 mm at 0.01 level (two tails), and positively correlated with root diameter in the class of 1< L< 2 mm at 0.05 level (two tails).