The present invention relates to a system and a method in the technique field of a power frequency magnetic field, and particularly relates to a system and a method for processing fish fries by utilizing a power frequency magnetic field. The system includes a power frequency magnetic field generating device, and an aquarium for placing fish fries is arranged on the middle part of a magnetic field coil of the power frequency magnetic field. The method includes steps as follows: step 1: immersing healthy fish fries in a 4% saline solution for a time of 5-10 minutes; step 2: placing the fish fries processed by the step 1 in the organic glass aquarium, and opening the power frequency magnetic field generating device to act on the fish fries. According to the invention, a digestive function of fish fries is influenced by the power frequency magnetic field and a digestive protease activity effect so as to accelerate development and growing of fish fries, and the system and method can solve a problem that the physical technology for processing fish fries in the prior art lacks acceleration to fish fry development and growing.