The extremely low Ta and Nb content in tantalum-niobium ores affects the sensitivity of conventional laser-induced breakdown spectroscopy (LIBS) techniques. Although the double-pulse LIBS technique offers a significantly improved analytical sensitivity, it suffers from a high equipment cost. Therefore, a double-pulse laser-induced breakdown spectroscopy (DP-LIBS) technique based on a single laser beam splitting configuration is proposed for the high-sensitivity detection of Ta and Nb elements in tantalum-niobium ores. A quantitative LIBS analysis model is developed based on the optimization of experimental parameters such as the distance from the focal point, acquisition delay, and laser energy. The results show that the proposed DP-LIBS system enhances the intensity of the characteristic spectral lines of the Ta and Nb elements by 3-4 times compared with single-pulse LIBS, and increases the detection sensitivity by approximately 2 times, where the detection limits of the Ta and Nb elements are 195.91 μg·g^-1 and 81.79 μg·g^-1, respectively. Therefore, the proposed technique is a promising method for the rapid and highly-sensitive quantitative analysis of trace elements of Ta and Nb in tantalum-niobium ores.