A new analytical method for detecting butyltin in seawater is presented. In this method, the solid phase microextraction technique for pretreatment of the butyltin compound was used and a new type Flame Photometric Detector (FPD) was designed. Use of this method to determine the butyltin contents in Qingdao coast seawater yielded convincing results. A new analytical method for detecting butyltin in seawater is presented. This method, the solid phase microextraction technique for pretreatment of the butyltin compound was used and a new type Flame Photometric Detector (FPD) was designed. Use of this method to determine the butyltin contents in Qingdao coast seawater yielded convincing results.