Abstract: To solve the problems of poor deep processing and utilization of tuna products, and to develop tuna processing products, we used yellowfin tuna (Thunnus albacares) as raw material to compare the effects of flavor protease, neutral protease, alkaline protease, papain and lipase on the amino acid nitrogen content and sensory score of pickled tuna. On the basis of single factor experiment, we determined the best salting conditions for tuna by orthogonal test, and carried out a correlation analysis of tuna before and after salting by electronic nose. The results show that the flavor protease was the best exogenous protease, and the best processing fomula was: 0.3% flavor protease, 50 ℃ and 3.5 h. Under these conditions, the mass fraction of amino acid nitrogen was 0.82 mg∙g⁻¹, and the sensory score was 36.3. The meat of pickled yellowfin tuna steak was delicious with good flavor.