This research intends to explore the characteristics of functional brain networks during intense urinary states in healthy adults. Methods: Healthy subjects were included and underwent resting-state functional near-infrared spectroscopy(fNIRS) testing when the bladder was full and empty, respectively. Automatic anatomical labelling atlas(AAL) was applied to divide the cerebral cortex into 23 regions of interest (ROIs), and interstate HbO2 levels were compared for each ROI. Gaussian graphical model with nonconvex regularization was built based on the time-series data of each ROI, and the edge weights of the graphical model indicated the strength of functional connectivity(FC). The backbone structure of the brain network of each subject was extracted and used to compare the difference in strength of the same side weights in the two bladder states. Finally, in each state, the time-series data of all subjects were averaged, resulting in total data for the construction of the graph model, and then the backbone subnetworks were extracted for visualization and analysis. Results: A total of 19 healthy subjects. The median HbO2 was significantly higher in the right supraoccipital gyrus during the bladder empty state compared to the bladder full state(P=0.0401). No significant interstate differences were seen in the remaining ROIs. The FCs that were significantly stronger in the full state were“left orbital middle frontal gyrus-right orbital inferior frontal gyrus”(P=0.0036) and“right temporal pole superior temporal gyrus-right middle temporal gyrus”(P=0.0245); and the FC that was significantly stronger in the empty state was“left superior frontal gyrus - left orbital middle frontal gyrus”(P=0.0411). Compared to the empty state, the frontal lobes had more and stronger internal and external FCs during the bladder-filling state, especially the left frontal lobe’s cross-hemispheric FCs with the right audiovisual, motor and somatosensory, cingulate gyrus-insula system, and ventral temporal lobe association systems. Conclusion: The functional brain networks related to urination awareness involve multiple brain network modules in scope, including the frontal-parietal system, somatosensory areas, audio-visual system, cingulate-insula system, and ventral temporal lobe associative systems. In terms of activity patterns, it exhibits characteristics of a functional dark network.