Two asymmetric perylene diimide small molecules were synthesized, namely N, N’-di(2-ethylhexyl)-1- (2-methoxyethoxy)-7- nitryl - perylene -3, 4, 9, 10-tertracarboxylic acid diimide (Ⅲ) and N, N’-di(2-ethylhexyl)-1- (2-methoxyethoxy)- 6, 7- dinitryl - perylene-3, 4, 9, 10-tertracarboxylic acid diimide (Ⅳ). It was synthesized from 3, 4, 9, 10-perylenetetracarboxylic dianhydride by via connect 2-methoxyethoxy and nitryl to the opposite sides of the molecular bay-positions. The structures were characterized by 1H NMR, 13C NMR and MS. We have used density functional theory to optimize the calculation of molecular spatial stereoscopic conformation, the molecular twisted backbone and distribution of electron cloud was also studied; Ultraviolet-Visible absorption spectra (UV-Vis) showed that there is obvious red-shift on the maximum absorption peak, and the peak width at half height broaden; Through the cyclic voltammetry (CV), we calculated that the HOMO and LUMO energies of molecule Ⅲ are −5.85 eV and −3.55 eV, the molecule Ⅳ are −5.87 eV and −3.62 eV. Finally, at a relative humidity of 50% in atmospheric environment, the device of organic solar cell was constructed that Ⅲ and Ⅳ were respectively blended with polymer of benzodithiophene-alt-polythiophene (PTB7-Th). The performance of the device that the JSC= 3.6 mA/cm2, VOC=0.30V, FF= 0.40, PCE= 0.42% and JSC= 4.00 mA/cm2, VOC= 0.25 V, FF= 0.41, PCE= 0.40%.