In this paper, monomer N-(4-hydroxyphenyl-1) 4-alkyloxybenzamide was obtained by the Williamson reaction, acylation, and aminolysis. Side-chain polysiloxane liquid crystal was then successfully synthesized by a grafting reaction of the monomer. The monomer and liquid crystal were characterized by Fourier-transform infrared spectroscopy, 1H nuclear magnetic resonance spectroscopy, differential scanning calorimetry, and polarization microscopy. The results showed that both monomer and polymer exhibited thermotropic smectic A behavior, and they were very stable within the studied temperature range. They may be very sensitive to both electric and magnetic fields because of their liquid crystalline properties.