Abstract: To compare the efficiency of seaweed fertilizers prepared by different extraction processes on rape, pot experiments were conducted to study the effects of acid- extracting, acid- alkali- extracting, Stanley enzyme-extracting and microbe-extracting seaweed fertilizers on rape growth. The results showed that Stanley enzyme-extracting and microbe-extracting seaweed fertilizers had moderate reaction conditions, and could be easily prepared, and the product appearance was fine, smooth and stable. Their effective substance contents, such as alginic acid, gibberellin and indole acetic acid, were higher than those in acid-extracting and acidalkali-extracting seaweed fertilizers. Hence the Stanley enzyme-extracting and microbe-extracting seaweed fertilizers were superior to the other two fertilizers both from the preparation process and the product quality. The plant height and chlorophyll value of rape under Stanley microbe-extracting seaweed fertilizer treatment were significantly higher than those under other treatments. Specifically, the plant height and chlorophyll value were 13.3% and 22.5% higher than those under acid-alkali-extracting seaweed fertilizer, and 23.5% and 26.9% higher than those under acid-extracting seaweed fertilizer treatment. Both the dry mass and fresh mass of rape did not show significant differences between enzyme- extracting and microbe- extracting seaweed fertilizer treatments, but significantly higher than those under other treatments. The fresh mass of rape under microbe-extracting seaweed fertilizer treatment was 12.6% and 15.8% higher than those under acid-alkaliextracting and acid-extracting seaweed fertilizer treatments, respectively. Our study indicates that the fertilizer efficiency sequence of seaweed fertilizers prepared by the four different extraction processes is: acidextracting＜acid-alkali-extracting＜Stanley enzyme-extracting＜ Stanley microbe-extracting.