The difference of degradation dynamics and final residues of 1.5%matrine·osthol AS in tomato and soil under open field and greenhouse conditions was studied,in order to provide theoretical references for pesticide usage in tomato and to improve safety procedure measures.The degradation dynamics and final residues were determined by HPLC with PSA solid phase extraction after 1.5%matrine·osthol AS was applied on tomato and soil in open field and greenhouse conditions. The results showed that,in two cultivation patterns the half-lives of degradation of matrine were 5.18—6.70 d in tomato and 7.45—8.08 d in soil,the half-lives of osthol were 1.70—1.99 d in tomato and 2.30—2.67 d in soil.The sampling time at 1,3,7 d after last pesticide application,the final residues of matrine in open field and greenhouse were ND—0.427 4 mg/kg and 0.010 2—0.522 8 mg/kg in tomato,and the final residues of osthol in open field and greenhouse were ND—0.388 7 mg/kg and ND—0.395 2 mg/kg in tomato,respectively.Matrine and osthol are easily degradable pesticides.The half-lives of degradation of matrine and osthol in greenhouse were longer than those in open field.With few exceptions,the final residues in tomato and soil in greenhouse were generally higher than in open field under the same application dosage,times and sampling interval.