The invention provides a thermochromic cellulose acetate composite material, as well as a preparation method and an application thereof. The composite material is prepared from at least the followingraw materials in parts by weight: 100 parts of cellulose diacetate, 0.5-15 parts of thermochromic masterbatches, 10-54 parts of plasticizer and 0-2 parts of an additive. The preparation method comprises the following steps: mixing the components, plasticizing and pelletizing to obtain the thermochromic cellulose acetate composite material. The composite material can be used in wearable products, can achieve the effect of color changes by responding to temperature change in indoor and outer door environments at 22-35 DEG C, so that excellent visual effect and anti-falsification property can beachieved, and the individual wearing requirement of consumers can be met.