AlGaAs/GaAs surface quantum wells (QW) with different well thicknesses are studied by in-situ photoreflectance spectra. The transitions between the sublevels are observed for 3 and 5 nm well samples, and the separation of 11H and 11L transitions are observed clearly. The results show the strong interaction between the sublevels and surface states. The transitions between the second subbands are also observed M-hcn the widths of the wells are 7 and 10 nm. The effects of the surface QW on the confined states have been studied using mass approximation theory. A model accounting the interaction of confined states with surface state is used to analyze the experimental results: the theoretical results are in good agreement with experiment.