The properites of a polyester short fiber-NR composites was investigated. The polyester short fiber-NR composites was made by the open mill. The properties of the composites, such as mechanical properties, vulcanization characteristics, and heat aging properties, with different quantities of polyester short fiber was studied. The experiment results showed that right amount of short fiber can increase mechanical properties of SFRC. The interface adhesion between short fiber and matrix is better, the composites have better the reinforcement and the heat aging properties.