In　this　letter,　the　beamforming　scheme　based　on　random　frequency　diverse　array　(RFDA)　is　newly　investigated　to　enhance　the　performance　of　covert　mmWave　communications.　First,　the　closed-form　expressions　of　covertness　constraint　are　derived　for　the　RFDA　and　the　conventional　phase　array　(PA)　beamforming　schemes,　respectively.　Then,　the　optimal　transmit　power　and　blocklength　maximizing　the　average　effective　covert　throughput　(AECT)　are　derived　for　both　beamforming　schemes.　Considering　the　pessimistic　scenarios　that　Willie　locates　in　its　desired　direction　as　Bob　(but　different　distances),　our　examination　shows　the　enhancement　of　maximum　AECT　by　adopting　the　RFDA　beamforming　scheme.　Besides,　in　this　case,　the　maximum　AECT　for　the　RFDA　beamforming　scheme　can　be　improved　while　that　for　the　PA　beamforming　scheme　remains　unchanged　as　the　number　of　antennas　enlarges.　Furthermore,　it　is　revealed　that　the　superior　performance　of　the　RFDA　beamforming　scheme　is　influenced　by　Willie＇s　location,　and　the　range　of　Willie　in　which　the　RFDA　beamforming　scheme　outperforms　the　PA　beamforming　scheme　is　obtained.