Abstract: A detection system and an operating method are provided. The detection system is used to estimate a degradation state of a battery device. The detection system includes a first operation circuit, a second operation circuit, and a processor. The first operation circuit receives voltage timing data of the battery device, and calculates a first reference value of the battery device according to the voltage timing data. The second operation circuit receives temperature timing data of the battery device, and calculates a second reference value of the battery device according to the temperature timing data. The processor provides state data related to the degradation state according to the first reference value and the second reference value.