Objective To study the effects of vision on human postural control and the connection mechanisms of the brain’s functional network. Methods 15 healthy male adults were required to perform 30 s of balanced standing on both legs with eyes open and eyes closed. The center of pressure (COP) and electroencephalograph (EEG) were recorded during balance. The sample entropy (sample En) of the COP was calculated. The phase lag index (PLI) in θ-, α-, β-band of EEG was calculated to construct the brain functional networks, and the clustering coefficient (C), characteristic path length (L), and the criteria (σ) of the small-world network were calculated based on graph theory. Results During balanced standing on both legs, the SampleEn of the COPY with eyes closed was significantly higher than that with eyes open (P<0.05). The mean value of PLI in the α-band under the eyes closed state was significantly higher than that under the eyes open state (P<0.05). The C and σ values in the α-band under the eyes closed state were significantly higher than those under the eyes open state, and the L value was significantly lower than that under the eyes open state (P<0.05). The frontal-central-parietal connectivity and the central-parietal connectivity strength in the α-band under the eyes closed state were significantly higher than those under the eyes open state (P<0.05). The average PLI and C values in the α-band were moderately negatively correlated with the SampleEn of COPY (P<0.05). The average PLI of the left prefrontal area, left parietal area, and left occipital area in the α-band under the eyes closed state had a moderate negative correlation with the SampleEn of COPY. The average PLI of the left central region and the right occipital area in the eyes-closed state was moderately negatively correlated with the SampleEn of COPY. Conclusions During the standing balance, when there is no visual input, the stability of body balance decreases, accompanied by enhanced brain network connectivity in α-band and the requirement for efficiency enhancement in information processing in the brain. The brain adopts different neural strategies when performing postural control under various visual conditions.