A stilbazium salt polystyrene was synthesized as a pre-polymerized organic material for Langmuir-Blodgett (L-B) film fabrication and nonlinear optical property study. This material can form stable monolayer on a water surface to be transferred onto solid substrates. Second harmonic generation (SHG) studies on monolayer showed that the second order polarizability per chromophoric group of this material was 1. 2× 10-28esu. Multilayers of two different types of this material have also been fabricated and studied by SHG measurement. The results are discussed.