A new method for obtain the derivative photoacoustic spectroscopy is proposed. A wavelength-intensity splitter is designed to obtain the derivative spectroscopy of photoacoustic spectroscopy with the help of a monochromator and a prism. Using the wavelength-intensity splitter, two light beams with identical intensity but lightly different are obtained in wavelenth at the same time. The two light beams are modulated and then folded in the photoacoustic detector symmetrically, so as to realize the difference of phtoacoustic signal. The derivative photoacoustic spectra is obtained by scanning the wavelength of monochromator. The first-order derivative spectra of photoacoustic spectra is obtained with the method. The derivative photoacoustic spectroscopy is endowed with higher resolution than that of photoacoustic spectroscopy.