In order to explore a nondestructive approach to predict total soluble solids (TSS) of Bamfild nave orange, multiplicative scatter correction (MSC) was used to preprocess the NIR spectra (1000~2500nm) of navel orange. Partial least square (PLS), interval partial least square (iPLS) and synergy interval partial least square (siPLS) methods were employed to establish the calibration models of TSS. The results showed that siPLS model was obtained with 17 intervals and the optimal combinations of intervals selected were No.4(1267~1355nm), No.5(1356~1443nm), No.9(1708~1795nm) and No.15(2236~2323nm). The coefficient of determination r was 0.9109 and RMSECV was 0.3312 in calibration set, and r was 0.8789 and RMSEP was 0.4487 in prediction set. It was achieved with six factors. This work demonstrated that NIR spectroscopy with siPLS model could not only select the efficient regions for TSS of orange and simplify the model, but also improve precision.