The photoluminescence (PL) properties of InN films grown by metal organic chemical vapor deposition (MOCVD) have been investigated. InN has a high level of background carrier concentration, which makes the Fermi level lie above the conduction band. By nonlinear fitting of the PL results, along with the energy band relations, we calculated the band gap of InN film to be 0.67 eV and the carrier concentration n=5.4×1018 cm-3. Thus we found a connection between PL results and the carrier concentration of InN films. In addition, we also studied the dependence of peak position and intensity of PL on temperature: the intensity of photoluminescence decreases as the temperature increases, and the peak position shows a red shift instead of an S-shape variation. Such a difference may be explained by a huge full width at half maximum of PL spectra. Also the concentration of carriers and the magnitude of the built-in electric field in the material may have influence on such a result.