The dynamic online analysis system consisted of focused beam reflectance measurement (FBRM) and automated lab reactor (Labmax) was used to determine the solubility of HMX in N,N-dimethylformamide (DMF),1,4-butyrolactone and cyclohexanone. The experimental solubility data were correlated with Apelblat model and polynomial empirical equation,respectively. The results show that the average relative deviations and the correlation coefficients of HMX solubility in DMF,1,4-butyrolactone and cyclohexanone are 0.5,0.4,0.009582 and 0.7,0.9,0.99565 for Apelblat model, and 0.9,0.6,0.033673 and 0.8,0.8,0.99768 for polynomial empirical equation,showing that the solubilities of HMX are well-fitted in the Apelblat model. 