Over the years a near-field superlens (NFSL) has received much attention because of its super-resolution beyond the diffraction limits. Till now the index matched NFSL is widely applied to the near-field imaging system under the loss-free assumption. However, the natural materials for a NFSL have intrinsic absorption loss, which prevents ideal image reconstruction and blurs the near-field image. In connection with this issue, we wish to address the compensation of blurred image in the lossy NFSL system through the analysis of optical transfer function and the full-wave numerical approach. The results to be drawn from this research are that we obtained a high-quality image of lossy NFSL through active phase correction of OTF using the index mismatch approach by tuning the wavelength of incident light. And this approach can be applied to a lossy NFSL image system in the optical, IR and THz regime.