A measurement method of explosive crystallization thermodynamic parameters based on optofluidics was proposed to obtain the crystallization thermodynamic parameters such as solubility and metastable zone width of explosive crystal， and the applicability of this method was verified by taking HNS explosive as a sample. The solubility of HNS in DMSO/DMF solvent system with volume ratio of 10∶0， 7∶3， 5∶5， 3∶7 and 0∶10 from 318.15 to 353.15 K and the metastable zone width of HNS in the above DMSO/DMF solvent system from 318.15 to 333.15 K were measured with a step of 5 K. Apelblat model and λh model were employed to fit the collected solubility data. The effect of solvent system on the metastable zone width was studied， and the crystallization parameters were screened. According to the classical nucleation theory， the apparent nucleation order m of HNS was calculated， and the nucleation mechanism of HNS by cooling crystallization was analyzed. The results indicate that the measurement method of crystallization thermodynamic parameters based on optofluidics exhibit exceptional applicability to HNS crystals. With the increase of temperature and the volume ratio of DMSO in the system， the solubility of HNS increases. With the increase of DMSO volume ratio in the system， the width of metastable zone becomes narrower. The optimum crystallization conditions are as follows： pure DMSO is utilized as solvent， the solution temperature is set at 333.15 K， and the solute concentration is 0.029 g·mL^-1. The value of m is approximately 4， which is not affected by the initial temperature. It can be inferred that the nucleation mechanism of HNS belongs to continuous nucleation.