We experimentally investigate the iodine sublimation process using nonlinear spectroscopy induced by high-intensity femtosecond laser filamentation in air. It is demonstrated that femtosecond laser filament can induce clean characteristic fluorescence emission of sublimated iodine molecules in air. By monitoring the fluorescence of the molecular iodine at 341.6 nm (the D→X1Σ+g transition), we observe by time-resolved measurements that the fluorescence signal varies as functions of the heating temperature and the distance from the measurement position to the solid iodine sample, showing the possibility of exploring the matter phase transform with femtosecond filament induced fluorescence spectroscopy.