The vegetation coverage was interpreted by using remote sensing information in northern region of China. The water and soil conservation effect coefficient was also calculated through vegetation coverage. The correlation between water and soil conservation effect coefficient and the difference between precipitation and evapotranspiration was negative. The correlation between water and soil conservation effect coefficient and the primary vegetation potentiality was positive. The significance was more than 0.01 level. So, the water and soil conservation effect coefficient may possible become a comprehensive index to evaluate regional ecological function in northern region of China.