An orthogonal re-heating double pulse laser-induced breakdown spectroscopy (RDP-LIBS) experimental setup is built. The Coptis Chinensis is selected as the research target and the spectral intensities and signal-to-background ratios of its characteristic spectral lines are used to evaluate the spectral characteristics. The detection sensibility is improved by the optimization of detection delay, the combination of two laser energy values, the pulse interval and other experimental parameters. Compared with those by the single pulse laser-induced breakdown spectroscopy (SP-LIBS) technique, the enhancement factor of spectral intensities by the RDP-LIBS technique for the four characteristic spectral lines of Fe, Al, Ca and CN are 4.0, 5.5, 10.0 and 3.5 times, respectively. The electron excitation temperature and the electron number density of plasma by the RDP-LIBS technique are both higher than those by the SP- LIBS technique.