Due to vertical stagnation of water and oxygen depletion by organisms, the oxygen minimum zone (OMZ) in the pelagic layer of ocean is characterized by low oxygen concentrations. The extreme shoaling of upper boundary of OMZ would lead to strong habitat compression and potential changes in ocean biogeochemistry. In addition, deoxygenation and concomitant biogeochemical changes in OMZ, including denitrification, sulfide production, and accumulation of bioavailability of trace metals, are multiple stressors for organisms under climate change. Previous studies of global OMZ metrics (i.e., boundaries, thickness and volume) mainly focused on their spatial distribution instead of interannual variabilities. Significant shoaling of upper boundary of OMZ has been observed regionally, and the deepen of the lower boundary as well as its volume expansion were also reproduced by model simulations. However, the long-term variabilities of global OMZ, which reflect dynamical and biochemical processes in the interior ocean, have rarely been assessed due to sparse observations. Here we evaluate global and regional OMZ variations from 1960 to 2019 based on global dissolved oxygen (DO) profiles from multiple observed datasets and horizontal spatial distributions of OMZ metrics. We define OMZ20 and OMZ60 as the regions where DO is lower than 20 μmol/kg and 60 μmol/kg, respectively. We find that upper boundaries of OMZ60 (-0.56 ±0.30 m/yr) and OMZ20 (-0.24±0.89 m/yr) show widespread shoaling trends in the global ocean. Upper boundaries of OMZ20 in the Bangle of Bay (BB) and North Pacific (NP) show shoaling trends more than 0.5 m/yr. Moreover, large shoaling trends (i.e., > 1 m/yr) of upper boundaries of OMZ60 are widely observed in the Arabian Sea (AS), BB and NP. However, lower boundaries of OMZ60 show divergent regional patterns with insignificant global shoaling trends, and they deepen in the tropical and southern subtropical oceans while shoal in the northern subtropical oceans. Thickness and volume of global OMZ60 are expanding at 1.75 ±0.87 m/yr and 5.92 ±147.90 km³/yr, respectively. The vertical expansion of global OMZ is probably linked to increased ocean temperature and enhanced stratification under climate change. More research on environmental drivers and future change of OMZ metrics is required. The shoaling of upper boundary of OMZ compresses epi- and mesopelagic aerobic communities’ habitats, which would increase the fishing loss. Therefore, vertical expansion of global OMZ should be accounted for in the management of marine environmental mitigation and biological conservation.