The invention relates to a method for analyzing the content of rare earth elements in thorium tetrafluoride. The method comprises the following steps: dissolving thorium tetrafluoride powder in an ammonium carbonate solution to obtain a first solution; adding hydrogen peroxide into the first solution, and centrifuging the obtained solution to obtain a water phase and a solid phase; adding an acid into the water phase, heating the water phase to obtain a second solution free from fluorine and ammonium, and dissolving the solid phase in nitric acid to obtain a third solution; mixing the second solution with the third solution to obtain a dissolution solution, and diluting the dissolution solution with nitric acid to obtain an introduction sample; repeating above steps without adding the thorium tetrafluoride powder to obtain a blank solution; transferring a plurality of parts of the dissolution solution, and respectively adding different amounts of a rare earth mixed substance solution to obtain multiple standard substance added solutions; and determining the rare earth elements in the blank solution, the standard substance added solutions and the introduction sample by using an inductively coupled plasma mass spectrometer. The method for analyzing the content of rare earth elements in thorium tetrafluoride can be used to highly-efficiently and accurately determine the content of rare earth elements in thorium tetrafluoride.