The invention discloses a combined detecting method for tetrabromobisphenol A and hexabromocyclododecane in an aquatic product. The method comprises the following steps of (1), performing sample preprocessing, extracting supernatant of a unit aquatic product sample and an internal standard substance by means of solid phase dispersion, purifying the supernatant by means of a filler, and obtaining extract of a to-be-detected sample; (2), executing a super-high-efficiency liquid chromatography-tandem mass spectrometry method on the extract of the to-be-detected sample obtained in the step (1) forobtaining the mass spectrum of the related peaks of the tetrabromobisphenol A and the hexabromocyclododecane of the to-be-detected sample; and (3), calculating the contents of the tetrabromobisphenolA and the hexabromocyclododecane in the sample according to an internal standard method. The invention provides the super-high-efficiency liquid chromatography-tandem mass spectrometry method for quick sample preprocessing is applied to analysis for quickly analyzing TBBPA and HBCD in the aquatic product. The combined detecting method has advantages of simple operation, high speed and high sensitivity. Furthermore the combined detecting method can satisfy a requirement for analysis and quantification of the TBBPA and HBCD in batch aquatic products.