The invention discloses an electrochemical method for detecting the activity of protein acetyltransferase. P2 templated silver nanoparticles and cucurbit [8] urea are added into a P1 modified gold electrode and a detection system of a p300 protein, the activity of the p300 protein is detected by electrochemical measurement, and the protein transferase activity is obtained; the amino acid sequenceof P1 is 11-mercaptoundecanoic acid (MUA)-GGGFRGKGGKGLGKGGAKA; and the amino acid sequence of P2 is FGGGASLWWSEKL. p300 is used as a model, and the silver nanoparticles are synthesized by a signal template P2, and assembled with a sensing template P1 through a cavity, so that the sensitivity of detection is ensured, high design flexibility is achieved, and meanwhile, the selectivity of HATs is enhanced. The development of the simple and practical electrochemical method capable of detecting HATs activity is expected to help early diagnosis of major diseases.