The material and structure of the cantilever beam have an important influence on the output response of piezoelectric energy harvester. In order to study the influences of different substrate materials on the contact piezoelectric energy harvesters under the low wind speed of 1.5~5.8 m/s. In this paper, the flexible PVDF piezoelectric cantilever beam structures with substrates of PVC, 304 stainless steel, 1060 aluminum and H68 brass are selected for comparative experiments and analysis. The results show that the output power of the cantilever structure based on 304 stainless steel substrate has the largest output power. Moreover, by calculating the structural parameters of beams with different substrate materials, it is found that the structural stiffness and amplitude reduction factor are the main factors affecting the output performance of piezoelectric energy harvester under low wind speed conditions. Under the same working conditions, when the structural stiffness of the beam is smaller, the starting wind speed of the contact piezoelectric energy harvester is lower, and the exciting force frequency of wind-induced vibration is higher. The smaller the amplitude reduction factor, the greater the output power of the cantilever beam.