Energy harvesting technology is a power-sourcing technology for wireless low-power applications. The piezoelectric cantilever vibration energy harvester is one of the important methods. However, the cantilever harvester is only effective in a limited narrow frequency bandwidth and is limited in practical applications. This paper summarizes the optimization methods proposed by researchers in recent years, and classifies them from the perspective of linear and nonlinear wideband method and frequency tuning method. These methods have positive significance for breaking the bottleneck of the narrow band of cantilever harvester. Subsequently, this paper introduces some recent research hotspots and key technical issues from different research ideas, such as low-frequency, multi-directional energy harvesting, etc., and summarizes the current applied research. Finally, the research on the insufficiency of the cantilever piezoelectric vibration energy harvester and the future development trend are considered.