The invention discloses a 5G green wireless signal shielding device and a shielding method thereof, and relates to the field of 5G mobile communication. The shielding device is characterized in that an antenna is connected with a signal processor, and a power supply is connected with the signal processor, the signal processor comprises a radio frequency processing module and a baseband processingmodule which interact with each other. The shielding method comprises the following steps: 1, searching cells; 2, solving MIB / SIB; 3, generating a PSS interference sequence; 4, generating an SSS interference sequence; 5, generating a PBCH DMRS interference sequence; 6, performing resource mapping; and 7, generating an OFDM baseband signal. The invention has the following advantages and positive effects: (1) the intensity of an interference signal generated by the shielding device only needs to be 3 dB greater than the signal intensity of a 5G public network, so that the signal shielding can be completely realized; 2, 5G uplink signals are not interfered, and the base station is not influenced; and 3, the transmitted interference signal only occupies a small amount of time-frequency resources, so that the power of the shielding device can be greatly reduced, and environmental protection and high efficiency are achieved.