Abstract: We used high performance liquid chromatography to determine malachite green (MG) in aquatic products, and optimized the factors affecting recovery, such as extraction method, KBH₄ amount, evaporation temperature, selection of solid phase extraction column and mobile phase, etc..The sample was extracted by homogenate and ultrasonic instrument, reduced with 6% KBH₄, vacuum-evaporated at 40 ℃, purified with PRS solid phase, and determined by the mobile phase of 75% acetonitrile with 25% ammonium. Thus, we obtain an accurate method which has simple pretreatment but high recovery.