Experiments with rape pot culture were carried out to investigate effects of bentenite improving soil fertilizer - conserving and increasing yields. The results suggested that with the use of bentenitc addictive along 0 - 5 %, the more addictive used, the more effect of improving soil fertilizer- conserving, the less of nireogen leaching. It could improve soil nutrient supply. It could also improve the growth of crops and increase the yeilds. The best economic usity of bentenite to sand soil was 5 % of soil gravity.