Abstract: Novel amphiphilic polysaccharide-based material carboxymethyl cellulose derivative (CMCD) was prepared by esterification of carboxymethyl cellulose sodium (CMC-Na) and tocopherol succinate via ionic liquid activation. The FTIR, ¹H NMR, X-ray diffraction (XRD) and thermogravimetry (TG) were used to characterize the molecular structure and thermal properties. The tebuconazole nanocapsules were prepared using ultrasound/rotary evaporation. The particle sizes and morphologies of the nanocapsules were determined by dynamic light scattering (DLS) and transmission electron microscopy (TEM) . The entrapment efficiency, loading rate and sustained-release performance of tebufonzol were detected by HPLC, and the fungicidal activity was also investigated using the medium method. The results showed that the amphiphilic carboxymethyl cellulose derivative (CMCD) was successfully synthesized with the critical micelle concentration (CAC) of 0.28 mg/mL. The particle size of the tebuconazole nanocapsules was 400-500 nm, the encapsulation efficiency was 50.8%, and the drug loading was 40.4%. The sustained-release test showed that, after 48 hours, the final cumulative release rate of tebuconazole-loaded CCMD nanocapsules was 77.78%. The bioassay results showed that the inhibition rate of the tebuconazole-loaded CMCD nanocapsules against Botryosphaeria dothidea still reached 17.67% after 12 days. At this time, the inhibition rate of the traditional tebuconazole 430 g/L SC was almost 0. The research indicated that the novel amphiphilic polysaccharide-based tebuconazole nanocapsules prepared in this work have good sustained-release performance and fungicidal activity.