Abstract: PPTA(polyphenylene terephthalamide) pulp was prepared by semi-continuous direct polycondensation using a co-current rotating and meshing twin screw extruder as main reactor.It has been found that the thickness of PPTA gel depends on the thickness of the slit of extrusion head.The thickness of PPTA gel has significant influence on gel maturing,relative molecular mass,aspect ratio and morphology of the pulp.