The principle of blade tip timing technology is introduced. The current state of research on the under-sampled signal analysis in the frequency domain for blade tip timing is reviewed. The applications of four sensor placement strategies in the frequency domain analysis of blade tip timing are discussed, including a single sensor, dual sensors, sensors with specific location constraints, and multiple sensors. Four approaches for the frequency spectrum analysis of undersampled signals are presented, which are time series fitting, band-limited signal reconstruction theory, sparse representation theory, and array signal processing, with an emphasis on their theoretical foundations as well as their strengths and limitations. The characteristics of the synchronous and asynchronous vibration analysis in the field of blade tip timing are discussed. Furthermore, four future research directions for frequency domain analysis of blade tip timing technology are identified, including uncertainty analysis of sampling, assessment of amplitude analysis validity, data analysis of novel blade tip sampling strategies, and intelligent feature extraction and fault diagnosis.