During the railways construction period,subgrade construction,tunnel excavation,etc.will induce soil and water loss,which has negative impact on eco-environment of the regions along the railway.In this study,the impact of soil and water loss for construction of the second line of Litang-Qinzhou railway was quantitatively analyzed and evaluated by using the SWII method.The results showed that the impact index value of soil erosion and water loss in the project was 0.11,which was 60% lower than the averaged value of impact indices of railway construction projects in China.The causes for the low index value included less occupation land(2.02 hm²·km^-1) and influence area(0.28 hm²·km^-1),little earthwork volume(3.86×10⁴m³·km^-1) and wasted excavation(0.28×10⁴ m³·km^-1), and small amount of soil and water loss(211.61 t·km^-1).In addition,we could reduce construction period and increase control area of soil and water loss to mitigate the impact of soil and water loss and protect the eco-environment of the regions along the railway.