This study realizes a portable sensor for dual sensing of oxygen and temperature using a digital color chip with a simultaneous measurement function of three colors, namely, red-green-blue (RGB). An ormosil sol-gel matrix is doped in the sensing film coating on the color chip with three fluorescent dyes. All dyes are excited using a 405-nm light-emitting diode. The emission wavelengths match the three RGB channels of the color chip separately without a spectral overlap. Under various temperatures and oxygen concentrations, the experimental results show that the developed sensor allows a simultaneous monitoring of both temperature and oxygen with good stability and has an excellent linear response in the oxygen concentration range of 0%-30% and the temperature range of 25-75 ℃.