The invention discloses a method for mixing and fermenting a sour salted fish based on neutral protease. The steps are as follows: the raw fish is cut into pieces after scales and viscera are removed;the fish pieces, rice noodles, salt, a 106-108 CFU/mL M3 bacteria solution of Weissella cibaria and a 10000-20000 U/mL neutral protease solution are mixed evenly and put in a container with the ricenoodles covering at the top layer. After 20-30 days of fermentation at 20oC-30oC, the sour salted fish is obtained. A weight ratio of the fish pieces, the rice noodles and the salt is (90-115) : (50-70) : (2-4). The additive amount of the M3 bacteria solution of Weissella cibaria is 0.006 mL-0.06 mL per gram of the fish piece, and 0.005-0.025 mL neutral protease solution per gram of the fish piece. The method for mixing and fermenting the sour salted fish based on neutral protease has the advantages of shortening fermentation period of the sour salted fish, lowering down biogenic amine contentin the sour salted fish, improving flavor and taste, and leading to a final smell similarity around 86%measured by an electronic nosewith the smell of the sour salted fish made by traditional methods.