Two novel polysilanes that bear an amphiphilic ammonium moiety in the side substituent are synthesize. The spreading behaviors of these polymers at the air-water interface, the LB deposition, and their spectroscopic properties are investigated. Utilizing the strong UV absorption of the Si-Si backbone attributed to the delocalized sigma electron, substantial knowledge on the conformation and orientation of the main chain is readily obtained by UV-visible absorption spectroscopic measurements. Compression of the polysilane monolayer at the air-water interface induces a blue shift of the sigma-sigma* band around 300 nm, which is reasonably attributed to the trans-gauche populational changes of the backbone. The Si-Si backbone aligns parallel to the dipping direction in the multilayered Langmuir-Blodgett films for both polysilanes.