  The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid
scintillator detector designed to explore many topics in fundamental physics.
In this paper, the potential on searching for proton decay in $p\to \bar\nu
K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a
clear three-fold coincidence signature that results in a high efficiency for
identification. Moreover, the excellent energy resolution of JUNO permits to
suppress the sizable background caused by other delayed signals. Based on these
advantages, the detection efficiency for the proton decay via $p\to \bar\nu
K^+$ is 36.9% with a background level of 0.2 events after 10 years of data
taking. The estimated sensitivity based on 200 kton-years exposure is $9.6
\times 10^{33}$ years, competitive with the current best limits on the proton
lifetime in this channel.
