A photoacoustic spectroscopy system which can measure the photoacoustic amplitude spectrum and phase spectrum simultaneously is constructed. Based on the conventional gas-microphone system, the phase measurement function is added to the system. The hardware configuration of the system is also optimized. It can scan wavelengths continuously from ultraviolet (UV) to near-infrared (NIR) regions within the range of 350~1000 nm with the minimal step length of 0.1 nm and the modulation frequency range of 10~2000 Hz. Using the virtual instrument software LabVIEW, the computer in the system can control instruments, set the experimental parameters, acquire and process data automatically. The front panel of the LabVIEW program can monitor the experiment dynamically and obtain the real-time spectra of both photoacoustic amplitude and photoacoustic phase. The system is evaluated with Ho2O3, and the normalized photoacoustic amplitude spectrum is consistent with the photoacoustic spectra reported by the existing literatures. The inclusion of camptothecin and nydroxypropyl-β-cyclodextrin is studied by the system, and the experimental results show that more information of the same sample can be obtained when combines photoacoustic phase spectrum with photoacoustic amplitude spectrum.