  The cross sections of $e^+e^- \rightarrow K^+K^-J/\psi$ at center-of-mass
energies from 4.127 to 4.600~GeV are measured based on 15.6 fb$^{-1}$ data
collected with the BESIII detector operating at the BEPCII storage ring. Two
resonant structures are observed in the line shape of the cross sections. The
mass and width of the first structure are measured to be
($4225.3\pm2.3\pm21.5$) MeV and ($72.9\pm6.1\pm30.8$)~MeV, respectively. They
are consistent with those of the established $Y(4230)$. The second structure is
observed for the first time with a statistical significance greater than
8$\sigma$, denoted as $Y(4500)$. Its mass and width are determined to be
($4484.7\pm13.3\pm24.1$) MeV and ($111.1\pm30.1\pm15.2$) MeV, respectively. The
first presented uncertainties are statistical and the second ones are
systematic. The product of the electronic partial width with the decay
branching fraction $ \Gamma(Y(4230)\to e^+ e^-) \mathcal{B}(Y(4230) \to K^+ K^-
J/\psi)$ is reported.
