  The measurement of the Cabibbo-favored semileptonic decay
$\Lambda_c^+\rightarrow \Lambda \mu^+\nu_{\mu}$ is reported using
$4.5~\mathrm{fb}^{-1}$ of $e^+e^-$ annihilation data collected at
center-of-mass energies ranging from 4.600~GeV to 4.699~GeV. The branching
fraction of the decay is measured to be $\mathcal{B}(\Lambda_c^+\rightarrow
\Lambda \mu^+\nu_{\mu})=(3.48\pm0.14_{\rm stat.}\pm0.10_{\rm syst.})\%$, three
times more precise than the prior world average result. Tests of lepton flavor
universality using $\Lambda_c^+\rightarrow \Lambda \ell^+\nu_{\ell}$ ($\ell=e,
\mu$) decays are reported for the first time, based on measurements of the
differential decay rates and the forward-backward asymmetries in separate
four-momentum transfer regions. The results are compatible with Standard Model
predictions. Furthermore, we improve the determination of the form-factor
parameters in $\Lambda_c^+\rightarrow \Lambda \ell^+\nu_{\ell}$ decays, which
provide stringent tests and calibration for lattice quantum chromodynamics
(LQCD) calculations.
