The processes of structure formation during the precipitation of hydroxypropyl cellulose from isotropic solutions in various solvents were studied using optical methods. It was found that with an increase in the average polymer concentration in solution during coagulation, a transition to cholesteric mesophase occurs. The transition is accompanied by a change in the shape and intensity of small-angle scattering polarized light patterns and a decrease in the pitch of cholesteric helix. During polymer coagulation from isotropic solutions, two stages of structure formation are detected, which manifest themselves in the form of scattering patterns of corresponding intensity and shape. The carried out studies make it possible to transfer the theoretical principles of liquid crystal state formation from the class of rigid-chain aromatic polyamides to semi-rigidchain cellulose ethers.