High-concentration CO₂ has a great impact on the accuracy of H₂S detection. Thus, this paper proposed a H₂S and CO₂ detection system based on fiber amplifier enhanced photoacoustic spectroscopy. A single distributed feedback (DFB) laser in series with a high-power erbium-doped fiber amplifier (EDFA) was taken as the photoacoustic excitation source for the high-precision detection of H₂S and CO₂ simultaneously. In addition, we analyzed the interference of CO₂ on H₂S detection at the selected H₂S absorption line and corrected the measured H₂S concentration with the detected CO₂ concentration. The results show that the deviation of the corrected H₂S concentration remains within -5% to 5%. Moreover, we used Allan variance analysis to calculate the detection limit of the system. When the integral time is 1 s, the detection limits to H₂S and CO₂ are 656.3×10 ^-9 and 25.2×10 ^-6, respectively; when the time is 100 s, the detection limits can reach 61×10 ^-9 and 2.6×10 ^-6, respectively. For trace H₂S detection, the normalized noise equivalent absorption (NNEA) coefficient is calculated to be 5.5×10 ^-9 cm ^-1·W·Hz ^-1/2. In conclusion, the proposed system has high detection accuracy and good stability.