Let S and be compact Riemann surfaces of the same genus g (g endowed with the Poincaré metric of constant negative curvature -1. par The authors show that for every , there exists an integer with the property: Assume that (1) injectivity radius of S and , and (2) the first eigenvalues of the Laplacian of S and coincide, then S and are isospectral. par The authors conjecture that the integer m will not depend on that is, the theorem holds with an integer which depends only on the genus. par For the proof, a model of Teichmüller space is described and the analyticity of the resolvent of Laplacian on this space is proved. Also the authors note that the injectivity radius is estimated by a finite part of the spectrum the number of eigenvalues of the Laplacian in the interval [1/4,1]).