Abstract: In this article, the computer aided engineering (CAE) and orthogonal design experimental was combined to study the warpage of injected parts of glass fiber reinforced polypropylene. Taking the car liner as an example, the warpage related parameters such as melt temperature, mold temperature, injection time, injection speed/pressure were investigated. It showed that the fiber content and mold temperature were two important factors affecting the warpage, which could be optimized to values giving minimum warpage.