The invention relates to a noncontact gas leakage detection system. The system comprises a support, a gas isolation shield device, a plurality of gas detection sensors, a plurality of gas flow sensors, a temperature sensor, an air blower, a gas detection sensor receiver, a gas flow sensor receiver and a computer processing system. The gas isolation shield device is away from a horizontal storage tank and used for forming a relatively isolated system on the surface of the horizontal storage tank; the gas detection sensors are distributed on the gas isolation shield device; the gas flow sensors are distributed on the gas isolation shield device; the temperature sensor is arranged in the middle of the axis of the gas isolation shield device; the air blower is fixedly arranged on one side of the gas isolation shield device; the gas detection sensor receiver is arranged at a corner of the support and connected with the gas detection sensors through cables; the gas flow sensor receiver is arranged at a corner of the support and connected with the gas flow sensors through cables; the computer processing system is connected with the gas detection sensor receiver, the gas flow sensor receiver and the temperature sensor through a signal circuit and used for receiving and processing acquired feedback data and real-time data.