A Si doped interlayer was introduced into the GaAs barrier layer to study optical properties of InGaAs/GaAs surface quantum dots (SQDs). Photoluminescence (PL) measurements show that luminescence of InGaAs/GaAs SQDs is strongly dependent on Si doping concentration. With increasing the Si doping concentration, InGaAs/GaAs SQDs show clearly different luminescence characteristics, including: PL peak position of SQDs shifts to red at first and then to blue; the dependence of PL peak energy on the cubic root of excitation intensity changes from linear to nonlinear; configuration interaction method shows reduced blue shift for PL band; time-resolved PL indicates a transition from nonlinear decay of type-II QDs to linear decay of type-I QDs. These experimental results indicate that Si doping fill the surface states and modify the surface Fermi level pinning effect, thus changing the luminescence characteristics of InGaAs/GaAs SQDs. This research provides a support for understanding and tailing the surface-sensitive characteristics of InGaAs SQDs for development of sensors.