The imprecise circuits engender more complexity for design and verification. The typical circuits are Taylor series. To process the imprecise circuits, we adopt a spectral technique, that is, Arithmetic Transform (AT). A new method based on AT is proposed in this paper to compute representations of imprecise datapaths for purpose of equivalence checking and component matching. From a Taylor Series, we devise an efficient algorithm to produce Arithmetic Transform (AT) which is a compact function representation. Also, a searching algorithm is introduced for calculating the imprecision between the specification and the implementation.