  Top squark (stop) is a crucial part of supersymmetric models (SUSY) to
understand the naturalness problem. Other than the traditional stop pair
production, the single production via electroweak interaction provides signals
with distinctive features which could help confirm the existence of the top
squark. In this paper, we investigate the observability of stop through the
mono-top channel of the single stop production at the future proton-proton
colliders, FCC-hh and SPPC, in a simplified Minimal Supersymmetric Standard
Model (MSSM). With the integrated luminosity of 3000 $\text{fb}^{-1}$, we can
probe the stop with mass up to 3.25 TeV by the mono-top channel at $5\sigma$
level. Considering the systematic uncertainty of 10%, the exclusion limit for
stop mass can be reached at about 1.5 TeV. Exclusion limits on stop mass and
higgsino mass parameter $\mu$ are also presented.
