P3HT/dodecylamine functioned carbon microspheres (D-CMSs) composite films were prepared by spin-coating method with D-CMSs and P3HT mixture chloroform solution, and the photovoltaic devices with structures ITO/PEDOT:PASS/P3HT:D-CMSs/Al were also fabricated. Morphology and structure of the composite films were characterized by field emission scanning electron microscopy, atomic force microscopy, Fourier transformation infrared spectrometry and X-raydiffractometry. Ultraviolet-visible spectrophotometry and photoluminescence spectrometry were used to characterize the optical property of the composite films. The results show that composite films with 1:1 ratio of D-CMSs to P3HT had optimum morphology and optical performance. The absorption of annealed P3HT:D-CMSs composite films was enhanced with a red-shift, and the crystallinity of film enhanced after annealing. The polymer solar cells based on P3HT:D-CMSs composite films exhibited a high V_oc of 0.840 V, suggesting D-CMSs is a promising acceptor for polymer cells. This would lay an experimental and theoretical foundation for further researching the fabricating polymer solar cells with new acceptors.