Abstract: In order to realize the rapid quantitative detection of copper and zinc in brass samples, three brass samples were studied by calibration-free laser-induced breakdown spectroscopy(CF-LIBS). Six characteristic spectral lines of copper and four characteristic spectral lines of zinc were selected as the analysis objects. Under the spectrum acquisition modes of a single pulse and an average of 10 pulses, the relative standard deviation (RSD) of characteristic spectral lines of copper and zinc were comparatively analyzed. The results show that under the condition of an average of 10 pulses, the average RSD of copper and zinc is decreased by 8.8% and 12.3%, respectively, compared with the single pulse. The mass fraction of copper and zinc in three brass samples are quantitatively calculated by CF-LIBS, the relative errors between the temperature of copper and zinc and the average plasma temperature are 5.2%, 0.9%, and 7.1%, respectively. The relative errors in copper mass fraction in the three samples are 5.6%, 0.5% and, 1.6%, respectively; The relative errors in zinc mass fraction are 9.2%, 2.0%, and 13.3%, respectively. CF-LIBS is expected to provide method support for the rapid and accurate detection of element mass fraction in brass and provide data and technical support for the further development of portable detection equipment for the element mass fraction of alloy samples.