Various solvents were treated on the cellulose fiber spun in our lab. Results showed that the lower the molecular weight of solvent, the higher the decrease of initial modulus of fiber and provided that the solubility parameter of cellulose is 25.66 the decrease of modulus was apparently high in two separate regions, region of high values. However, in the middle of two regions the decrease of initial modulus was nil or dull. This means that cellulose chains are associated with each other by two forces, first, by dispersion forces between the top and bottom sheets of chains and by hydrogen bonding between the similes of sheets.