The invention relates to a nuclear reaction liquid which realizes nuclear fusion on the basis of acoustic cavitations and a preparation method thereof. The nuclear reaction liquid disclosed by the invention contains such nuclear reaction materials as tritium and a compound of tritium and lithium. The invention belongs to the technical field of the controlled thermal nuclear fusion. The nuclear reaction liquid of the invention mainly consists of the compound of tritium and lithium and heavy water with the mixed weight proportion mean value from 80 to 20. The three preparation methods of the nuclear reaction liquid of the invention are available as follows: 1. a neutron producer with proper energy is adopted for irradiating the lithium compound to have the nuclear reaction to generate the lithium compound containing the tritium and the lithium compound containing the tritium is dissolved into the heavy water to obtain the nuclear reaction liquid; 2. the lithium compound is dissolved into the heavy water in advance and a neutron producer with proper energy is adopted for irradiating the mixture to have nuclear reaction to generate the tritium and therefore to obtain the nuclear reaction liquid; 3. the tritide and the lithium compound are directly dissolved into the heavy water to obtain the nuclear reaction liquid.