Abstract: The forming process of a bicolor plastic part with characteristics of small size, high appearance and complex structures was analyzed, and then its injection mould was designed.Considering of an ejecting difficulty due to the plastic part obliquely placed in the mold, which resulted in nonperpendicular between the ejecting direction and stress surface, an inclined ejector mechanism was designed.Moreover, the corepulling mechanism with a Tshaped block, angle pin and ejector plate were designed with regard to the small size of the part and multiple corepulling places.For the reasons that the secondary injecting gate could not be set on the surface of the part and there were a lot of sliders around the part, a gating system with hot runners turning to the cold ones was also designed.The experimental results indicated that the mould structure was reasonable and reliable and met the requirement for production.