The image reconstruction of diffuse optical tomography (DOT) for near-infrared brain functional imaging is a severely ill-posed inverse problem. Different from the widely adopted multi-mode imaging method for providing anatomical-prior to DOT, this paper proposed an optical self-guiding scheme, called OT-DOT, and the corresponding image reconstruciton algorithm is developed. The numerical and phantom validations are performed for the proposed method. Numerical reconstruction results indicate that quantitativeness ratio (QR) reconstructed with OT-DOT for the target is about 4.2 times bigger than that with traditional DOT for the known top layer thickness(TLT). QR from OT-DOT can be more 92% when the estimation error of TLT is less than ±10%. The noise-robustness testing indicates the reconstruction ability of OT-DOT and traditional DOT are roughly the same. Phantom experiments performed using a continuous-wave DOT system show that the reconstructed results with the proposed method is better than those with traditional DOT.