The invention discloses a copper carbonate loaded titanium dioxide ultraviolet photocatalyst and a preparation method thereof. The photocatalyst comprises the following raw materials in parts by weight: 1 part of titanium dioxide, 0.2-0.5 part of inorganic carbonate and 0.001-0.5 part of inorganic copper salt. The method comprises the following steps: firstly, dissolving inorganic carbonate in water to obtain an inorganic carbonate aqueous solution with the molar concentration of 0.1-1.0 mmol/L; secondly, dispersing titanium dioxide in the inorganic carbonate aqueous solution to obtain suspension liquid; finally, slowly adding the inorganic copper salt into the suspension liquid obtained in the step (3), uniformly stirring, washing and standing, filtering by filter paper, and drying in vacuum at 60-100 DEG C for 4-8 hours to obtain the copper carbonate loaded titanium dioxide ultraviolet photocatalyst. Compared with a conventional load technology, the loads of transition metal oxides all need to be electrically calcined, and in the method, the preparation cost does not exist and the electrical energy does not need to be used; the preparation cost of the photocatalyst meets the condition that the cost of each 500 g of the photocatalyst is increased by less than 0.5 yuan on the basis of the cost of titanium dioxide.