We aim to use fQSM to investigate the phenomenon of negative BOLD with a visual stimulation task. fQSM data of 14 subjects was reconstructed with the phase information. The results show the negative BOLD is located in the identical brain region of Calcarine in both fMRI or fQSM analysis. In the future, we will optimize fQSM reconstruction method. A reliable fQSM is able to improve the understanding of the underline mechanism of fMRI BOLD.