The invention provides a preparation method of special titanium dioxide for plastic profiles. Industrial titanium dioxide is sequentially crushed and sieved, treated titanium dioxide is subjected to SiO2 inorganic coating in a fluidized bed and then subjected to organic surface modification, and special titanium dioxide for the plastic profiles is prepared. The heat resistance and light resistance of titanium dioxide are effectively improved, the plastification property of titanium dioxide in the plastic processing process is improved, and besides, the prepared plastic profiles have excellent mechanical performance.