A review of cell traction forces (CTFs) measurement based on Biological Micro Electromechanical Systems (BioMEMS) microposts matrix is presented. CTFs are exerted by cells and transmitted to the underlying substrate through focal adhesions and close contacts, which is essential for cells movement. Cells probe the mechanical compliance of the extracellular matrix (ECM) in part by locally deforming it with nanonewton-scale traction forces. Precision measurement of CTFs is significant for many researches such as cell biology and tissue engineering and so on. Enabled by the advancement in BioMEMS technology, surface treated high aspect ratio Polydimethylsiloxane (PDMS) microposts matrix devices, which serve as BioMEMS sensors for detecting cellular nanoforces and studying in vitro cell mechanics, have been developed. Closely spaced vertical microposts matrixes were designed to encourage cells to attach and spread across multiple microposts, and to bend the microposts like vertical cantilevers as the cells locomote on the surface. Using this dense and discrete matrix of microposts rather than a conventional continuous substrate, CTFs can be directly measured and quantified by processing the microscopy images of the deformations of microposts. The resolution of the force was in tens of nN/?m scale. At first, the conventional CTFs measurement methods were concisely summarized. Then BioMEMS microposts matrix method was described in detail, including principle and fabrication process, surface treatment and cell experiment results. Furthermore, high aspect ratio structure collapse problem was investigated.