A new measurement method of thermal analysis for solid state nuclear tracks is proposed. The annealing heat emitted by the unit mass of solid state nuclear tracks in heavy particles of the sample is determined via micro-thermal analysis method. Hence, the number of solid state nuclear tracks in the unit mass of sample is determined. In particular, this paper introduces the method and its significance to measure the number of α-particles nuclear tracks in apatite by measuring the annealing heat of α-particles nuclear tracks. In addition, the mechanism of the measurement and potential applications are discussed. solid state nuclear tracks probe, thermal analysis, annealing heat, apatiteOne of the most important ways to promote progress in science and technology is to constantly explore new measurement means. Currently, the research in this area is rather active both at home and abroad [1][2][3][4] . When the same particle is ripped into the same solid target and the dose of particle into the target is not very high, an incident particle will have a nuclear track which corresponds to a certain degree of energy deposition; there is a certain relationship between the total damage energy of deposition in the target and the number of nuclear tracks in the target. There should also be a certain relationship between the annealing heat emitted from the deposition energy of target and the number of nuclear tracks of the target. The number of unit mass of solid state nuclear tracks can be determined by measuring the annealing heat emitted from unit mass of solid. We proposed that the method of thermal analysis to detect solid state nuclear tracks is feasible [5] . Based on this idea, the number of α-particles solid state nuclear tracks of unit mass of apatite sample is determined.The sample to be tested for solid state nuclear tracks at different time period is irradiated with the same known irradiation source. The irradiation dose G of the irradiated sample at each time period is calculated and the annealing heat Q of unit mass of irradiated sample at each time period is determined. In right-angle coordinate system, the curve between irradiation dose G and the annealing heat Q is made. The slope a (the proportion of the annealing heat to the total irradiation dose) of straight line by fittings and the intercept b (corresponding to the inherent annealing heat Q 0 of the sample to be tested) is obtained respectively, and then the irradiation dose (G 0 =b/a=Q 0 /a) and solid nuclear track density ρ 0 (ρ 0 =G 0 /E) of the sample can be calculated. As the sample is in the same target which is irradiated by the particles with the same type and energy, the determined value is the number of nuclear track of unit mass of the sample before irradiated by the known irradiation source. Whether the sample is suitable for straight-line fitting and the quality of the linear relationship is judged by fitting coefficient.