This invention provides a method for manufacturing parts with a built-in channel. Two kinds of materials with different melting points are used, the material with the lower melting point is a molding element with an arbitrary shape, the material with the higher melting point is powdered, and the material with the low melting point is wrapped and positioned in the powder with the high melting point. When the preparation is completed, the low-temperature material is melted down, and the channel with the random shape is formed after sintering. In the application that the metal parts need supply water, air, or oil, instead of the channel acquired by mechanical splicing or the channel molded by 3D printing technology, this method in the invention is with a wide application range, the lower cost, and the simple and controllable technology, and is suitable for mass production and with very broad market prospects.