The invention discloses a machining method for a mobile phone model product part having a carbon-fiber effect. A first side part of the part is an appearance surface. The machining method comprises the following steps of machining a carbon-fiber sheet; machining an inner core; adhering the carbon-fiber sheet onto the first side part of the inner core, and ensuring the carbon-fiber sheet to be completely fitted with the first side part of the inner core to obtain a primary machined part; fixing the primary machined part into a cavity of a positioning jig, reserving a space surrounding the primary machined part inside the cavity of the positioning jig, filling epoxy resin into the space, and molding an epoxy resin layer for wrapping the primary machined part to obtain a secondary machined part; utilizing a machine tool to machine, and ensuring the first side part of the secondary machined part to be completely consistent with the appearance surface so as to obtain the part. By adopting the machining method, the appearance effect of the carbon fiber, and a purpose for verifying the appearance effect and the material by a designer can be realized, the production cost can be reduced, and the production period can be accelerated.