It is interesting that the electronic spin gap is opened in the localized states of nanosilicon doped with oxygen, where spin splitting of the individual two-level +/- 1/2 states isolated in the localized states increases by 1-2 order of magnitude (on the order of 100 meV). The opening spin level effect in the localized states is observed in experiment, which originates from the twin states of quantum vibration measured in the photovaltaic system consisting of the quantum dots and the quantum layers of silicon prepared by using a pulsed laser in an oxygen environment. The opening spin level effect in the localized states is investigated by using density functional theory (DFT) in the simulation models of the quantum dots and the quantum layers of silicon with Si=O bond or Si-O-Si bond on surface. The detailed simulating calculations show that the broader splitting gaps of the electronic spin polarization confined at the individual impurity atoms occur in the localized states, which are consistent with experimental results. A physical model is built to explain the opening spin levels effect, in which the opening spin level effect mechanism in the localized states originates from the quantum confinement at doping atom. The opening spin level effect will improve the fidelity of information stored and processed within such a spin qubit.