New NLO-functionalized poly(1,4-phenylenevinylene) (PDNAPV) containing 2,4-dinitroanilino group, was synthesized through organic-soluble precursor pathway. The prepared polymer was characterized with NMR, FT-IR, W-visible and other spectroscopic methods to identify its properties. The result from the thermal analyses and spectroscopic techniques showed that the precursor was converted into PDNAPV around at 200 degreesC without any decomposition of 2,4-dinitroanilino group. The second-order NLO coefficient (chi ((2))) Of poled PDNAPV film was determined by second-harmonic generation technique. The resonant chi ((2)) value was 26 pm/V and the resonance-corrected value (chi ((2))(0)) was 12 pm/V, which was stable at room temperature for a month.