The invention relates to a load monitoring and early warning method of an in-service pipeline support hanger. The method comprises the following steps: uniformly attaching four resistance strain gauges on a suspender of the pipeline support hanger along the same circumference at intervals, wherein the four resistance strain gauges are all electrically connected with a strain tester, the four resistance strain gauges form a Wheatstone bridge circuit, when a load on the suspender changes and the suspender deforms, the tissues of the resistance strain gauges change, so that the load of the suspender is measured; performing real-time measurement on the load of the pipeline support hanger, and sending an alarm when a measured value exceeds an early warning value by +/- 5%; and when the slope ofa load-time curve of the pipeline support hanger is abrupt, primarily judging an abnormal working condition. By adopting the method provided by the invention, a non-manual onsite inspection mode canbe realized, the operation state of all pipeline support hangers are remotely monitored and recorded in real time, a position of function can be determined in advance to send the alarm in the case ofabnormality or failure, data analysis is performed by the own software of the equipment to evaluate the cause of the abnormality or failure of the pipeline support hanger.