Micro/nanomaterials refer to the materials or devices with their physical dimension or basic unit size in the range of 10 nm to 10,000 nm. It has been demonstrated occasionally and qualitatively that the properties of Micro/nanomaterials exhibit the following characteristics: can not be achieved through extrapolate the knowledge system based on their bulk counterpart; the traditional technologies and methods are in sufficient to study them efficiently; multi fields are always involved in the real applications of Micro/nanomaterials. These characteristics require the researchers to find and develop new tools and methods continuously in order to fabricate, monitor, manipulate and test these materials effectively. Dual beam focused ion beam (FIB) can not only be used to image, monitor and manipulate the materials but also has the ability to etch samples to expected geometry and deposit materials for welding et al. at nanometer resolution. Consequently, dual beam FIB has become a powerful tool in the research of nanomechanics. In this paper, the state of the art applications of FIB in nanomechanics research will be reviewed. Its limitation and future development will be also discussed.