A compact fiber-based quartz-enhanced photoacoustic spectroscopy system requiring no extra optical lens has been developed for the detection of acetylene. The system is based on a common fiber or an axicon fiber to conduct the light. Experimental results show comparable detection sensitivity to that of tapered fiber-based photoacoustic spectroscopy systems. The system is easy to adjust and has low insertion loss and is thus well suited for small portable sensor applications in the future. A numerical model based on actual beam profiles was furthermore developed as part of the study to investigate the optimal positions of the fibers and to verify the experimental results.