In order to investigate the behavior of soil erosion on the slope of the different underlaying surface during construction,the experiment with natural rainfall on Xichang-Panzhihua high-way was conducted,to quantify the runoff and soil loss. The re-sults show that:① the main type of soil erosion is gully erosion,the amount of soil erosion caused by gully erosion is higher than that by surface erosion. ② The principal factor causing soil ero-sion on the slope of the embankment is individual amount of pre-cipitation,the width of the embankment and rain intensity. ③ The principal factor causing soil erosion on the cutting slope is indi-vidual amount of precipitation,the width of the cutting slope and rain intensity. ④ The principal factor causing soil erosion on the slope of the dumped soil area is individual amount of precipitation,the width of the flat roof and rain intensity. There are well linear relationships between the amount of soil erosion and the principal factor,and their correlation coefficient are 0.935 7-0.999 8. In order to investigate the behavior of soil erosion on the slope of the different underlaying surface during construction, the experiment with natural rainfall on Xichang-Panzhihua high-way was conducted, to quantify the runoff and soil loss. The re-sults show that: ① the main type of soil erosion is gully erosion, the amount of soil erosion caused by gully erosion is higher than that by surface erosion. ② The principal factor causing soil ero-sion on the slope of the embankment is individual amount of pre-cipitation , the width of the embankment and rain intensity. ③ The principal factor causing soil erosion on the cutting slope is indi-vidual amount of precipitation, the width of the cutting slope and rain intensity. the dumped soil area is individual amount of precipitation, the width of the flat roof and rain intensity. There are well linear relationships between the amount of soil erosion and the principal factor, and the ir correlation coefficient are 0.935 7-0.999 8.