Overload represents a significant challenge for pilots in flight, with a substantial impact on flight safety. Currently, the primary method of protection is the utilization of inflatable anti-G suit to address instances where blood is concentrated in the lower extremities. The inflatable air pressure of the anti-G suit varies in response to different overload conditions, which in turn affects the pilot's sensory and brain loads. However, this change has not yet been fully explored. To investigate the neural effects of pressure from the anti-G suit under different degrees of overload, this paper employs a pressurized simulation methodology. The subjects' brain state changes during the simulation are measured through electroencephalogram (EEG), and comparative calculations are performed using microstate and functional connectivity. The final results demonstrate that varying inflation levels of the bladder anti-G suit can influence the microstate and functional connectivity. The Duration, Coverage, Occurrence, and transition probability (TP) characteristics of microstate C demonstrated significant variance across three distinct levels of overload. The mean increase in Phase Locking Value (PLV) for overload 3 relative to the absence of overload was 13.8%, and the number of channel synchronizations underwent a transition from 7 to 62.