The present invention discloses a method for improving frozen prepared fish fillets. The method comprises the following steps: step 1: selecting a fresh live fish, removing scales, head, internal organs and bones, cutting the fish into 2-3mm fillets, and conducting washing and draining; step 2, adding, in parts by mass, 1.5-2 parts of a compound fish fillet tissue improver into every 100 fish fillets, adding 1.0-1.2 parts of salt, 0.5-0.6 part of monosodium glutamate, 0.01-0.1 part of I+G, 0.08-0.15 part of white pepper powder, 3-8 parts of starch and 30-65 ice water, and conducting vacuum rolling and pickling; step 3, conducting vacuum packaging, and conducting pickling 12-16h; and step 4, fast freezing the fillets until the center temperature of the fish fillets is -18 DEG C or below, and conducting freezing storage. The method maintains the nutritional value, the flavor and the taste of the prepared fish fillets during freezing and transportation process. The fish fillets are extremely resistant to boiling, the cooked fish fillets are still fresh, the fish fillets are shrunk-proof and fuller, and the yield is increased. The fillets are slightly brittle and free from peculiar taste in mouth feel, have no loss of raw material nutrients, and are suitable for a plurality of cooking methods such as hot pot.