The major composition of otoliths is biomineral aragonite. In the past two or three decades, quite a few achievements have been made in the study of fish otoliths, but no advances in researches on the thermoluminescence characteristics of the fish otoliths have been reported in literature. In this paper, thermoluminescence characteristics of otoliths of the wild carps (cyprinoid) in the Baiyangdian Lake of Hebei Province and the Miyun reservoir of Beijing were studied, and the difference of energy gap (E) between the fish otoliths in the two regions was analyzed. The experimental results indicate that such thermoluminescence curve parameters as Glow Peak (T), Thermoluminescence Intensity (I), Integral (S) and Half Width (W) of the fish otoliths from the Baiyangdian[JP3] Lake are greater than those from the Miyun reservoir, and the stability of thermoluminescence curve parameters and energy gap (E) of the former is weaker than that of the latter. Compared with things of the Miyun reservoir, the electrons and vacancies trapped in otoliths of the Baiyangdian Lake are more likely to escape. According to the investigation, the Baiyangdian Lake has suffered heavier pollution andeutrophication than the Miyun reservoir. Therefore, the thermoluminescence curve characteristics of the fish otoliths are quite sensitive to water quality and water environment, and this can be regarded as an important indicator to the contamination degree of the water.