Objective To explore the physiological protective effect of extended-coverage (full coverage below the armpit) liquid-filled anti-G measures on miniature swine during high +Gz exposure, and validate the effectiveness of the measures, so as to provide basic experimental data for the research on extended-coverage liquid-filled anti-G suit. Methods Miniature swine were randomly divided into 2 groups:control group (without any anti-G measures, n=10) and protection group (with extended-coverage liquid-filled anti-G measures, n=9). A human centrifuge was used to simulate +Gz exposure (baseline 1.4 G, onset rate 1 G/s, peak 8 G, duration 60 s). The changes in eye-level arterial blood pressure (EABP) and +Gz tolerance of miniature swine during high +Gz exposure were observed. Results The +Gz tolerance of miniature swine in the protection group was significantly higher than that in the control group (28.22[19.99, 251.22] G·s vs 7.58[3.65, 19.57] G·s, P<0.01). The decrease of EABP of miniature swine during peak +Gz exposure in the protection group was significantly lower than that in the control group ([109.03±3.45]% vs[176.92±11.84]%, P<0.01). The mean pulse-pressure difference of EABP of miniature swine in the control group during peak +Gz exposure was lower than that before +Gz exposure ([8.06±2.79] mmHg vs[36.96±9.80] mmHg, P<0.01; 1 mmHg=0.133 kPa). There was no significant difference between the mean pulse-pressure difference of EABP of miniature swine in the protection group during peak +Gz exposure and that before +Gz exposure ([48.66±8.74] mmHg vs[45.75±8.82] mmHg, P>0.05). Conclusion The use of extended-coverage liquid-filled anti-G measures can significantly mitigate the reduction of EABP induced by +Gz, maintain smooth pulse-pressure difference, and improve +Gz tolerance of miniature swine.