The clay was strengthened with natural xanthan gum, and the unconfined compressive strength characteristics of improved clay under different curing time and xanthan gum content were studied through a series of unconfined compressive strength tests. And the reinforcement mechanism was analyzed deeply. The test results show that xanthan gum as an additive can improve the unconfined compressive strength of clay to a great extent, and the compressive strength of improved clay samples increases with the increase of xanthan gum content and time, and finally tends to be stable. The optimum content of xanthan gum to improve clay is 1.5%, and the best curing time is 14 days. When the curing time is 14 days, the strength of the improved clay samples containing 0.5%, 1.0%, 1.5% and 2.0% xanthan gum increase by 13.43%, 20.85%, 29.87% and 34.70% respectively. Xanthan gum matrix enhances the integrity and cohesion of soil samples by enhancing the cohesion of clay particles, so as to enhance the compressive strength of clay samples. The research results can provide a certain reference basis for the practical engineering application of clay strengthened with xanthan gum.