In order to solve the problem of nanoparticle dispersion in liquid crystal and improve the stability of liquid crystal phase, this paper innovatively proposed a method for in-situ synthesis of nanoparticles. Using noble metal acetate as precursor and reducing agent, liquid crystal as template and protective agent, and controlling different conditions such as reaction temperature and precursor concentration, gold nanoparticles with different particle sizes and morphologies were prepared, and their effects on liquid crystal phase transition behavior and blue phase temperature range were studied. By in-situ synthesizing 7.0 nm gold nanoparticles in the blue phase of liquid crystal, the nanoparticles are evenly dispersed and the blue phase temperature range is widened by 20%. This method of in-situ synthesis of nanoparticles in liquid crystals provides new ideas and applications for the composite of inorganic nano and organic materials.