The zero-field spin splitting and Zeeman splitting in the In0.53Ga0.47As/In0.52Al0.48As quantum well (QW) were extracted by a Shubnikov-de Haas oscillations (SdH) beating pattern analysis under different tilt angles between QW plane and external magnetic field. It is found that the zero-field spin splitting Δ0 increases with increasing carrier concentration while the effective g-factor |g*| decreases. The further calculation indicated that the decrease of |g*| with concentration is ascribed to the nonparabolic effect of the band structure.