Plastic heat exchangers have attracted more and more attention because of their superior resistance to chemicals and fouling. However, the thermal conductivity of plastic materials is much lower than that of metal, which limits the wider application of plastic heat exchangers. In this study, polypropylene-based hollow fibers as a heat-conducting medium for heat exchangers was developed by melt-mixing polypropylene with graphite particles and maleated polypropylene (PP-g-MA). Results show that the addition of graphite fairly improved the crystalline, thermal stability and conductivity of the polypropylene resin and further, improved the heat transfer efficiency of polypropylene-based hollow fiber heat exchangers. The overall heat transfer coefficient of 15.0 wt % graphite modified polypropylene hollow fiber heat exchangers reached 1228.7 W/(m(2).K), which is 5 times higher than that of pure PP-based hollow fiber heat exchangers, and the overall conductance per unit volume reached 1.1 x 10(6) W/(m(3).K). Further, the heat transfer efficiency increases fairly with the increase of the fluid flow rate, especially with the flow rate of the tube-side. The optimized operation mode is that the hot water flows on the tube-side and the cold water flows on the shell-side.