[Objective] The root distribution characteristics of Hippophae rhamnoides ssp. sinensis, Hippophae rhamnoides ssp. taiyang, and H. rhamnoides ssp. mongolica “Wulanshalin” in a feldspathic area, and the characteristics of soil erosion resistance under the forests were analyzed in order to provide new tree species options for improving the local ecological environment. [Methods] The soil profiles were excavated in the field to obtain the root-soil complexes, and the root scanning and disintegration test were performed indoors. [Results] ① The vertical distribution patterns of roots for the three seabuckthorn species were similar. Root length and root volume gradually decreased with increasing soil depth, and roots were mainly located in the 0—60 cm soil layer, accounting for 90.96% of the total root amount for H. rhamnoides ssp. sinensis, 83.38% for H. rhamnoides ssp. taiyang, and 74.93% for H. rhamnoides ssp. mongolica “Wulanshalin”. Thick roots were mainly located in the 0—40 cm soil layer. The thick roots in the horizontal direction were mainly located in the range of 0—20 cm from the base of the plant, and the fine roots were mainly located in the range of 20—100 cm. The farther away from the base, the fewer the fine roots. The overall root system was distributed in a shallow layer. ② The change trend of soil disintegration rate under the H. rhamnoides forest was basically the same. The average disintegration rate of the surface soil at 0—20 cm was the lowest, and the rate gradually increased with increasing depth. In the horizontal direction, the farther away from the base of the plant, the greater the average disintegration rate of the soil. The soil disintegration rate followed the order of: H. rhamnoides ssp. sinensis (3.18 g/s)> H. rhamnoides ssp. taiyang (1.27 g/s)> H. rhamnoides ssp. mongolica “Wulanshalin” (1.21 g/s). ③ There was a significant correlation between soil disintegration rate and root distribution of seabuckthorn. In the vertical direction, it was affected by both coarse and fine roots, while in the horizontal direction, it was mainly affected by fine roots, which have a greater effect on soil and water retention. [Conclusion] The root content of H rhamnoides ssp. taiyang was higher than that of H rhamnoides ssp. mongolica “Wulanshalin”, and the root distribution characteristics were more closely related to the change law of soil disintegration rate under the forest, which is more suitable for soil erosion prevention and control in the soft sandstone area.