Impact source location is an important research topic in the field of aircraft structural health monitoring. The impact location method based on stress wave direction perception can effectively overcome the application limitations of time difference of arrival location method which depends on wave velocity, which is suitable for impact location monitoring of aircraft′s complex structures. In this article, the response characteristics of piezoelectric fibers to impact stress waves are analyzed. Aiming at the characteristics of impact stress wave signal for plate structures, such as broad frequency, dispersion and multi-modal components, the Shannon complex wavelet transform is used to extract the narrowband signal of the peak value of the stress wave energy. Combined with simulation analysis and experiments, it shows that the main energy component of the stress wave generated in the low-speed impact plate is A0 mode Lamb wave. Based on the directional response characteristics of piezoelectric fiber to Lamb wave, the piezoelectric fiber sensor with 45° “strain rosette” structure is optimized and prepared. The propagation direction of the stress wave is represented by the propagation direction of narrowband Lamb wave with peak energy, an impact source location method based on the sensing of the stress wave direction by piezoelectric fiber sensor is proposed. Experimental results show that the proposed impact source location method based on the sensing of the stress wave direction by piezoelectric fiber sensor is accurate and effective, and the average distance location error is 17. 2 mm. The research results provide a stress wave direction sensor and a structural impact location method that is independently from the stress wave velocity, which has certain theoretical research significance and engineering application value.