In order to promote the overall construction of the intelligent railway and to realize the intelligent high-speed railway, the communication infrastructure of high-speed railway will apply the 5th Generation Mobile Communication Technology(5G) to build the 5G for railway system. 2.1 GHz band is expected to be the bearer band for the 5G for railway system. The high-speed rail platform is the functional core of the loading and discharging of passengers and the cargo, and its propagation characteristics at 2.1 GHz need to be studied urgently. The wireless channel in the high-speed rail platform of Xiamen North Station at 2.1 GHz is characterized through Ray-Tracing(RT) simulations. Based on the simulation results, the channel parameters in the high-speed rail platform scenario are analyzed, including Root-Mean-Square Delay Spread(RMS DS), azimuth angular spread of arrival/departure, elevation angular spread of arrival/ departure(ASA/ASD, ESA/ESD), Cross-Polarization Ratio(XPR) and cross-correlations of the above parameters. Based on these results, relevant suggestions are provided for the design and evaluation of the 5G for railway system in the high-speed rail platform scenario.