The utility model discloses a portable trace gas detection system, which comprises a sampling module, a detection module and an equipment master controller, wherein the sampling module comprises an enrichment tube and a heater strip, wherein the enrichment tube is used for collecting and enriching a gas sample in predetermined enrichment time, and the heater strip is positioned in the enrichment tube and is used for heating the gas sample in the enrichment tube so as to release the concentrated gas sample in the enrichment tube through a heating manner; the detection module comprises a sensing cavity, a check valve and a sensor array, wherein the inlet of the sensing cavity is communicated with the outlet of the enrichment tube through a first pipeline; the check valve is arranged on the first pipeline; the sensor array is positioned in the sensing cavity and is used for detecting the gas sample sampled by the enrichment tube when the check valve is opened; the equipment master controller is used for controlling the heating time of the heater strip, opening and closing of the check valve and operation of the sensor array according to the enrichment time, and receiving detection signals of the sensor array to carry out data acquisition and processing.