The invention discloses an automatic monitoring system and monitoring method for quality change of an energetic material. The automatic monitoring system comprises a sample container, a heating constant-temperature apparatus, a movement control apparatus, a weighing apparatus, a numerical-value display system, an alarming system and a computer, wherein the heating constant-temperature apparatus, the movement control apparatus, the weighing apparatus, the numerical-value display system and the alarming system are connected with the computer, the heating constant-temperature apparatus is used for heating and thermally insulating a sample in the sample container, the movement control apparatus is used for moving the sample container and controlling the heating or weighing of a sample, the weighing apparatus is used for weighing the sample, the numerical-value display system is used for display a temperature and weight of the sample, the computer can record the monitoring data, the samplecontainer is provided with a handle, and a thermal insulation material is arranged between the heating constant-temperature apparatus and the weighing apparatus. By adopting the automatic monitoring system and monitoring method, the long-time quality monitoring for a plurality of samples at various temperatures can be realized, and the automation degree is high.