The invention provides a device for preventing ice crystals from spreading in subcooled water. The device comprises an anti-spreading pipe, a crystallization enhancement device, an air blower and pipelines. The device is characterized in that the anti-spreading pipe comprises an anti-spreading pipe inlet, an anti-spreading pipe outlet and a cold water flowing channel, a shell is arranged on the periphery of the cold water flowing channel, the shell is provided with a structure connected with an external air source, an air chamber is formed between the peripheral surface of the cold water flowing channel and the shell, a communicating structure is arranged on the pipe wall of an inner pipe of the cold water flowing channel, and the communicating structure enables the inner circumferential surface of the cold water flowing channel to form an air cushion layer; and the anti-spreading pipe outlet is connected with an inlet pipe of the crystallization enhancement device through one pipeline, a crystallization enhancement device outlet is connected with the air blower through one pipeline, and the air blower serves as the external air source to be connected with the anti-spreading pipe. According to the device for preventing the ice crystals from spreading in the subcooled water, countercurrent spreading of the ice crystals can be effectively blocked, the interior of a subcooled water heat exchanger is prevented from icing, flowing channel blocking is avoided, and stable and reliable operation of a cold water type dynamic ice slurry making process is guaranteed.