Studies of the effect of polyethlene oxide on the retention and drainage property of bleached sulfate wheat straw pulp, mixture of bleached sulfate wheat straw pulp and bleached wood pulp, and reed pulp systems have been made, which proved that polyethlene oxide is an excellent flocculating agent. Adding a little polyethlene oxide to the stock system can obviously improve the drainage property and increase the retention of fines, with a better effect in wheat straw system containing more fines, and less effect in wood pulp system. It should be noted that the effect brought about by polyethlene oxide comes from the bridging effect which is subject to the influence of various physical-chemical conditions, therefore, strict control over various conditions during processing should be maintained.