Ecological slope protection in highway engineering can not only prevent soil erosion effectively, b ut also has obvious effects on the reconstruction of biotope and the recovery of eco-system. Four types of typical ecological slope protection in Ba′nan and Nan′an Districts of Chongqing City, i. e. , bare slope, rhombic-structure grassing slope protection, tree slope protection and grassing slope protection, were selected to study the changes in soil erosion rate, relative coefficient, average soil erosion modulus, vegetation coverage, soil ingredient, etc. on each side slope. Results show that:(1) Among the four types of ecological slope pro-tections, the protective effect of the rhombic-structure grassing slope protection was the best; the tree slope protection, better than the grassing slope protection; and the bare slope, the worst. (2) The change of soil ingredient was affected not only by soil loss, but also by vegetation. (3) The soil and water conservation effect of the grassing slope protection was better than that of the rhombic-structure slope protection. In the late period, grass coverage increased slowly and thus the recovery effect of the grassing slope protection was worse than that of the rhombic-structure slope protection. (4) For the necessary elements in vegetation growth, soil loss for the rhombic-structure slope protection was relatively balanced.