Based on the actual railway tunnel engineering, combined with the test and energy analysis of rail blasting vibration, a research has been conducted on the blasting vibration effect and its control of existing railway tunnel under the influence of blasting construction of ultra-close adjacent tunnels. Wavelet packet decomposition and its norm preservation in Matlab have been used to decompose the blasting vibration signal, thus working out the track of blasting vibration in different frequency band energy distribution, obtaining the energy percentages of different frequency bands, and fitting the energy attenuation formula to further quantify the wave energy variation of iron rail. By fitting the monitoring data, the Sudowski formula suitable for the site conditions of Langkou Tunnel can be obtained. An analysis has been made of the attenuation law of blasting seismic wave of railway track under ultra-close distance, thus obtaining the formula for the calculation of the safe charge quantity and distance under the condition of Langkou tunnel site.