The piezoelectric microelectromechanical system(MEMS) provides a versatile platform for various high-performance filters, oscillators and sensors, etc.. The aluminum nitride (AlN) MEMS contour mode resonator (CMR) has the advantages of large operating frequency span, high quality factor, small size, ability to integrate multi-frequency devices on a single chip and compatible with integrated circuit(IC) technology, etc., and has good prospects for application. In this paper, the principle, typical structure, fabrication process and applications of AlN MEMS CMR are comprehensively overviewed, and the future developments of CMR technology are analyzed.