On the basis of a principle of self-consistent of mechanics of composites new analytical decisions for 11 effective electric, magnetic and elastic constants of the unidirectional fibrous composite with various polydisperse structures are received. Numerical calculation and the analysis of influence on effective constants of a composite with piezoelectric PVF fibers in a ferrite piezomagnetic matrix of value of the volume content of fibers and inversion of properties of phases in comparison with known solutions of the generalized singular approach for a statistical mix and an asymptotic method of averaging for ideal periodic structure is carried out.