This paper reviews some important problems in micro/nanomechanics: 1) similarity methods and scale effect in micro/nanomechanics; 2) surface force in micro/nanomechanics; 3 ) failure analysis of micro/ nanoelectromechanical system; 4) thermal stress and thermal fatigue in micro/nanoelectromechanical system; 5) technologic mechanics of micro/nanoelectromechanical system.