This paper describes a specific approach to detcting the tensioningdegree of circular saws besed on the study of the choice on those major indexesfor describing the tensioning state of circular saws, with 8031 single-chipcomputer as leading parts and the calculation method of base 2 and complexsequence of FFT Algorithm as its core. The experiments in the detection of dozens of circular saws of different kinds and sizes demonstrate that the quantitative analytic approach posed and detecting methods developed in this paper are feasible in worksites.