In this research, a new polymorph of florfenicol (form B) was discovered and successfully prepared. The new polymorph was characterized and identified by powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) techniques. It was found that form A has lower melting temperature while higher fusion enthalpy. The solubility of both florfenicol polymorphs in methanol, 2-propanol, acetone, acetonitrile, ethanol, and ethyl acetate were experimentally determined from 278.15 to 318.15 K with a dynamic method. For all tested solvents, the solubility data of florfenicol form B are higher than those of form A. The modified Apelblat model, the NRTL model, and the lambda h model were adopted to calculate the solubility of florfenicol two forms with satisfactory correlation results. In addition, the dissolution thermodynamic properties of florfenicol form A and form B, including dissolution enthalpy, dissolution entropy, and Gibb's dissolution energy in all tested solvents, were obtained. Combining the results of DCS determination, the solubility, and all the dissolution thermodynamic data, it was confirmed that florfenicol polymorph A and polymorph B belong to the enantiotropic polymorph system.