In this work, we present the results of our analysis of medium-resolution LAMOST spectra of late-type candidate members of the Pleiades with the aim of determining the stellar parameters, activity level, and lithium abundance. We used the ROTFIT code to determine the atmospheric parameters (Teff, logg, and [Fe/H]), along with the radial velocity (RV) and projected rotation velocity (vsini). Moreover, for late-type stars (Teff<=6500K), we also calculated the H{alpha} and LiI 6708 net equivalent width by means of the subtraction of inactive photospheric templates. We also used the rotation periods from the literature and we purposely determined them for 89 stars by analyzing the available Transiting Exoplanet Survey Satellite (TESS) photometry. We derived RV, vsini, and atmospheric parameters for 1581 spectra of 283 stars. Literature data were used to assess the accuracy of the derived parameters. The RV distribution of the cluster members peaks at 5.0km/s with a dispersion of 1.4km/s, while the average metallicity is [Fe/H]=-0.03+/-0.06, in line with previous determinations. Fitting empirical isochrones of Li depletion to EW measures of stars with Teff<6500K, we obtain a reliable age for the Pleiades of 118+/-6Myr, in agreement with the recent literature. The activity indicators H-alpha line flux (F_Ha_) and luminosity ratio (R'_Ha_) show the hottest stars to be less active, on average, than the coldest ones, as expected for a 100-Myr old cluster. When plotted against the Rossby number R_O_, our R'_Ha_ values display the typical trend with a steep decay for R_O_>0.2 and a nearly flat (saturated) activity level for smaller values. However, we still see a slight dependence on R_O_ in the saturated regime which is well fitted by a power law with a slope of -0.18+/-0.02, in agreement with some previous work. For three sources with multi-epoch data we have found LAMOST spectra acquired during flares, which are characterized by strong and broad H-alpha profiles and the presence of the HeI-6678 emission line. Among our targets we identify 39 possible SB1 and ten SB2 systems. We have also shown the potential of the LAMOST-MRS spectra, which allowed us to refine the orbital solution of some binary and to discover a new double-lined binary.