Multi-Modality fusion is one of the hottest discussed issues in the current research of medical image processing and it has a deep impact on the cognitive science and clinical treatment. In this paper, an fMRI-constraint equivalent dipole model (FC-ECD) based on ICA is proposed to solve the fusion of fMRI and EEG. The ICA is adopted as a preprocessing step to exclude the noise and select the available ERP components. At the same time, it can provide a prior estimate of the number of dipoles. Then considering the spatial information provided by fMRI, the selected ERP components are localized by FC-ECD model based on an ideal four-sphere head model. Thus it can reduce the computation time dramatically. Finally, the simulation study proves the correctness and validity of the method proposed in the paper and the human study coincides with the physiology fact.