The shape change in microprofile extrusion was investigated using a capillary rheometer with two different die orifices:a trilobal and a elliptic orifice. The material used in extrusion was fiber-grade polypropylene. The result showed that during microprofile extrusion the shape of extrudate deviated greatly from that of the die orifice. The size of extrudate increased with the increase of the extrusion speed and temperature but decreased with the increase of the drawing speed. Furthermore, water cooling was found to be beneficial in reducing shape change. For the trilobal shape, the shape change of trilbolal leaf in the width direction was much larger than that in the length direction. For the elliptic shape, the shape change along the minor axis was larger than along the major axis.