Abstract: For conventional solar photovoltaic/thermal（PV/T）system,the photothermal and photoelectric conversion processes are coupled. Thus,the solar full-spectral utilization efficiency is not high. In order to decouple the photoelectric and photothermal conversion processes,in this paper,the spectral and energy performance of the PV/T system were investigated when the Ag,CNT,and CNT/Ag nanofluids are used as the media. Firstly,the spectral properties of nanofluids with different concentrations are tested.Secondly,the effects of different concentrations of CNT/Ag nanofluids on the electrical and thermal efficiency of the PV/T systems are studied by experiments. The results show that compared with independent Ag nanofluids,the solar spectral transmittance in the PV cell response range for 1×10~6,3×10~6,5×106μg/m~3,and 1×10~7μg/m~3CNT/Ag nanofluids are increased by 8.6%,9.3%,8.5%,and 9.2%,the solar spectral absorptivity not in the PV cell response range are increased by 30.4%,44.5%,58.4%,and 56.7%,respectively. The electrical efficiency of PV/T system is up to 8.2%,and the thermal efficiency is up to 45%. When the concentration of CNT/Ag nanofluid is 5×10~6μg/m~3,the filtering efficiency is reached to 18.3%,while the thermal and electrical efficiency approached to 43% and 7%,respectively.