Abstract: Difference of soluble solids content (SSC) of apples was compared with static detection of near-infrared spectroscopy and online detection of near-infrared spectroscopy. The characteristic wavelength bands of SSC were searched by interval partial least square (iPLS) regression in the wavelength range of 600-950 nm (static) and 600.02-950.92 nm (online). The models of SSC were developed in static and online measurement mode. The online model was inferior to the static model with correlation coefficient of 0.78 and root mean square error of prediction (RMSEP) of 1.04 oBirx. The results show that it is inferior to statically determine SSC for online determination SSC of apples by NIRS technique.