Ten pyrazolin-oxadiazole molecules were optimized with density functional theory at B3LYP/6-31＋G* level. On the basis of the optimized structure, natural bond orbital charge analysis were carried out, and electronic absorption spectrum and the second-order nonlinear optical properties β₀ were calculated with TD-DFT (TDB3LYP/6-31＋G*) and FF method (B3LYP/6-31＋＋G**), respectively. The results indicated that these molecules had good nonlinear optical properties with 10⁴ order of magnitude a.u. (10^－28 esu) of β₀ value. On the basis of A2 molecule, one-sided introduction of group made the maximum absorption wavelength red-shifted, and enlarged their second-order nonlinear optical properties.