We perform a theoretical investigation about the excited state intramolecular proton transfer (ESIPT) reaction for a novel 2-(2-hydroxy-3,5-dimethyl-phenyl)-benzooxazole-5-carboxylicacid (HDPBC) system. The ultrafast excited state process is due to the low potential barrier, which should be the reason why only one fluorescence peak can be observed in previous experiment. Comparing the potential energy barriers in different aprotic solvents, we present nonpolar solvents play roles in facilitating ESIPT process for HDPBC molecule. This work not only clarifies the detailed ESIPT mechanism for the novel HDPBC system and explains experimental phenomenon, but also present that solvent effects could control the ESIPT process.