The authors processed cotton stalks into fiber and particles,and combined them with recycled plastics,polypropylene（PP）and polyethylene（PE）,to prepare cotton stalk fiber/plastic composites by hot pressing.The composite panel properties were tested to evaluate the effects caused by the cotton stalk shapes and panel processing factors.The results showed that: 1) The composites made from the cotton stalk particles had better properties than those made from cotton stalk fibers;2) Density,hot-pressing temperature and the cotton stalk/plastic ratio had a great effect on the cotton-stalk-fiber/polypropylene panel properties.Under optimized conditions,the cotton-stalk-fiber /polypropylene panel properties exceeded the specifications of national standard GB/T 4897.6-2003,GB/T 4897.7-2003 for structural particleboards.