The experiment aimed at the flow and heat transfer characteristics of different forms of nanometer particles in the oscillating heat pipe（OHP）.At the same pressure，the same inclination of heat pipe and different liquid filling rates

the flow and heat transfer characteristics of Cu-H2O nanofluids were investigated and compared with distilled water to study the effect of multiphase flow of steam，fluid and different forms of nanometer particles on heat transfer in heat pipe.The experiment indicated that multiphase flow of steam，fluid and different forms of nanometer particles in the OHP strongly affected heat transfer，and under specfic condition，heat transfer could be enhanced.