This paper presents a Fourier transform photoacoustic spectroscopy （FT-PAS） system based on a differential resonant photoacoustic cell （DPAC）, and systematically evaluates its performance for broadband and simultaneous multi-gas detection. Uniform modulation of a broadband light source is achieved through phase modulation via an interferometer and intensity modulation via a mechanical chopper, enabling efficient integration of Fourier transform spectroscopy with a resonant photoacoustic detection module. Broadband detection of single-component gases, including methane and acetylene, as well as their multi-component mixtures, across the 1-20 μm spectral range was carried out using a tungsten halogen lamp and a carbon globar thermal source. The results demonstrate that FT-PAS, combining the strengths of both Fourier transform and photoacoustic spectroscopy, exhibits characteristics such as broad spectral response, high resolution, parallel multiplexing, zero background interference, and wavelength independence. These attributes enable its use for broadband and simultaneous multi-gas detection, with potential applications spanning the full spectrum from the visible to the infrared region, and even extending into the terahertz range.