The solar cells based on the blend of MEH-PPV (poly(2-methoxy-5-(2′-ethylhexoxy)-1,4-phenylene vinylene) as the donor and PCBM(1-(3-methoxycarbonyl)-propyl-1-1-phenyl-(6,6)C61) as the acceptor are fabricated. We analyzed the influence of composition on the performance of the device by measurements of atomic force microscopy, photoluminescence spectroscopy, dark current density-voltage(J-V) curve of charge-only device, wavelength response of photoconductiveity and J-V curve. The highest efficiency is achieved at the 1∶4 (MEHPPV:PCBM) weight ratio. The good performance is attributed to reasons such as the optimized interpenetrating network, effective charge separaption and rapid charges transport in bicontinuous path. We obtained an open circuit voltage of 0.8V, short circuit current density of 3.47mA/cm2 and fill factor of 55.9% under 100mW/cm2 Air-Mass 1.5 solar simulator illumination, yielding a 1.55% power conversion efficiency.