We tested for fourteen trace elements in samples collected from the Ordovician strata in Datun coal field. The vertical concentration variation of these trace elements is reported. The relationship of the variation to the water-beating capacity of the Ordovician strata is discussed. The minimum concentration of eleven (of 14 total) trace elements appears in the lower Majiagou formation. The maximum concentrations mainly appear in the Badou and Jiawang formations: eight maxima are located in Badou and four more are in Jiawang. The study of karst development and the water-bearing capacity of Ordovician strata shows that karst is well developed in the Majiagou formation and there is a consequent high water-beating capacity in this formation: Badou and Jiawang formations are contrary to this situation. The results illustrate that the minimum concentrations of most trace elements within certain Ordovician formations can be taken as strong evidence for the existence of a well developed karst and a high wa-ter-bearing capacity.