The invention relates to a talcum powder-polyester composite material and a preparation method thereof. The method comprises: (1) mixing 1 part by weight of a coupling agent, 10-100 parts by weight of glycol and 0.1-10 parts by weight of water, adjusting a pH value to 1-6 with acid, and hydrolyzing for 0-1 hour; (2) mixing the coupling agent hydrolysate and 30-1000 parts by weight of the talcum powder for 5 minutes to obtain the active talcum powder; and (3) mixing 0.1-10 parts by weight of the active talcum powder, 70-80 parts by weight of terephthalic acid and 20-30 parts by weight of the glycol with stirring, adding 0.01-1 part by weight of a catalyst, heating to 70-90 DEG C, dehydrating under vacuum until the water content is less than 1.0 %, re-heating to 220-240 DEG C, esterifying for 6-10 hours, adding 0.01-1 part by weight of an additive, vacuumizing to a vacuum degree of 80 Pa or less under a temperature of 240-260 DEG C, and polymerizing for 1-3 hours to obtain the product.