Blasting must be performed in excavating a foundation pit in a densely-populated residential area. However, the pit is very close to civil residential housings as well as very close to pipelines of utilities like communication, power and gas pipelines. The shortest distance between the boundary of the pit and the gas pipeline is only 2m. In order to assure blasting safety, the standard for controlling blasting seismicity was established and seismic monitoring is conducted. The monitored results were used to guide the excavation.