Abstract:According to requirement of the National Afforestation Proj ect assisted by the World Bank，the soil erosion monitoring installations had been installed and observed on January 1 1992 in demonstration forest land of slash pine．The observation showed that lost amount of water and soil and nutrient was at maximum in the first year after planting and decreased with the increase of planting time．There were no significant difference between treatments with different measures．The range of runoff in both planting plotand non planting plot was 179.9～28.Ot·hm-2·a-1 and the soil loss was 73.1～3.4kg·hm-2·a-1 in fouryears，which was lower than the permissible lost of national standard in these areas．The tree growth ofslash pine exceeded the standard of high-yield-forest．It was proved that the dominant factor of influencingthe soil and water losses was the disappearend and recovering of vegetation in a area．In the monitoringdemonstration forest，the trees grew well so that the aim of cultivating forest and protecting environmentwas obtained．