At present, the photometric measurement (photometric sphere) sensor used in the LED measurement instrument is composed of a silicon photoelectric diode and the corresponding visual spectral response correction filter. In order to make the spectral response function of detector the same with the spectral luminous efficiency function V(λ) of CIE standard observer, it is generally composed of several filters. Due to the limitation of material and technique, the sensors of some instruments have some difference in spectral matching, the standard light source that is used in the instruments when leave the factory(it usually adopts 2856K filament lamp) will cause obvious deviations with the measured LED photometric value, and it tends to be more obvious for some monochrome LED. Therefore it should adopt the high precision photometric detector that spectral response curve is better conformity at each wavelength, or adopts spectral radiation measurement, and does the weighted integral by computer, to get a exact measurement results. Otherwise, it must adopt LED standard sample tube for calibration or correction of instruments, to get relatively consistent results.