Abstract: To reduce the risk of high-altitude sickness in tunnel construction workers operating on plateaus, a gradual and intermittent hypobaric hypoxic acclimatization technique was proposed. In a stratified randomized controlled trial, eight healthy lowland residents were randomly assigned to either a control group or a hypoxic exposure group. A hypobaric hypoxic chamber was used to simulate a gradient altitude environment ranging from 2,500 m to 5,000 m. A 7-day resting exposure protocol was applied with 3 hours of daily training under a stepwise ascending altitude scheme. The results show that this acclimatization approach significantly reduces the incidence rate and severity of acute mountain sickness (AMS) based on Lake Louise Score (LLS). Resting blood oxygen saturation increased by 6.98%, heart rate decreased by 17.24%, and the compensatory elevation in tidal volume (VT) recovered close to the baseline level at sea level. This short-term, 7-day acclimatization protocol overcomes the prolonged duration required by traditional staged acclimatization strategies and effectively satisfies acclimatization demands for high-altitude tunnel construction.