Manmade unavailable action for economy is the major reason thatcauses sever soil loss in YiMon mountainous region. The principal harmand destruction of soil loss to ecological environment and economy construction is as follows

that land deteriorates

production yield decreases

deposition of river and reservior or pond affects the bonefit of engineering

ecological environment worsens

natural disasters occur frequently.To periorm soil and water conservation of YiMon mountainous regionwell should be in accordence with the ecological economy princiles

thatthe first is to uphold entirty of the system

taking the small watershedas a unit to harness soil loss of YiMon mountainous region comprehensively

the second is to insist on the principle of structure

regulating agricultural arrangement rationally

and the third is to persevere the principle of correlation

making prevention and protection when working onharness.