In this study, wool fabrics were treated with different concentration of chitosan sulfamic acid solution under using 3-glycidyloxypropyltrimethoxysilane (GPTMS) as a crosslinking agent. The structure of treated wool fabrics was investigated by SEM, DSC-TG. Treated wool fibers had a irregular surface appearance, showed the presence of amounts of Nano SiO2 and their aggregates deposited onto surface of wool fibers. The thermal properties were obviously enhanced. Treated wool fabrics is more stable in higher temperature than that of untreatment. Treated wool fabrics were dyed with weak acid red B, and dyeing behaviour were studied by means of by light reflectance measurements. The color strength (K/S value) of treated wool fabrics obviousily increased from 5.33 to 31.68 by comparison with the untreatment. As a result, it can be concluded that the chitosan sulfamic acid solution with GPTMS treatment could improve the weak acid red B low temperature dyeing on wool. Further, low temperature dyeing of wool fabrics with chitosan-sulfamic acid is safe, so the results obtained are quite promising as a basis for possible future industrial application.