The invention discloses a system for and a realization method of railway GSM-R wireless communications against three order intermodulation interference. The system includes an antenna system and a receiver, and further comprises a first filter, a low noise amplifier and a second filter. The first filter is connected with the antenna system, and the low noise amplifier is connected with the receiver through the second filter. GSM signals received from the antenna system enter the low noise amplifier to be amplified after passing the first filter, then enter the second filter and finally enter the receiver. The first and the second filters are IM3 filters. By connecting in series the two filters, and adding the low noise amplifier, out-band rejection of the whole receiving system is very good, a noise factor of the receiving system is reduced and the GSM-R system is greatly improved.