The invention provides a preparation method of a material for an outdoor tent. The preparation method comprises the following steps: enabling TC cloth to be dipped in caustic soda solution, adding ananti-ultraviolet agent, taking out the TC cloth, and placing in chloroacetic acid water solution, taking out, washing by using mixed solution of ethyl alcohol and water, and drying; enabling 1-5 partsof sodium alginate by weight, 0.2-2 parts of polyethylene glycol by weight, and 1-5 parts of a dust preventive by weight to be dispersed in distilled water, stirring, to obtain first mixed solution;enabling the treated TC cloth to be dipped in the first mixed solution, and adding 1-2 parts of a cross-linking agent by weight, reacting for 1-1.5 h in 40-50 DEG C, drying, washing by water, and drying again, to obtain the material for the outdoor tent. The anti-ultraviolet agent, the dust preventive and the cross-linking agent are added in a preparation process of the material for the outdoor tent, and various raw materials are interacted and mutually affected, so the prepared material for the outdoor tent is guaranteed to have good dust tightness and anti-ultraviolet performance.