A new subclass of nonsingular H-matrices named \(GSDD_1^{**}\) matrices is studied in this paper. The relationship between \(GSDD_1^{**}\) matrices and other subclass of nonsingular H-matrices is discussed by numerical examples. Moreover, the infinity norm bounds for the inverse of \(GSDD_1^{**}\) matrices are given, and the effectiveness of the corresponding results are illustrated by numerical examples. Finally, based on the definition of \(GSDD_1^{**}\) matrices, a new subclass of P-matrices, which is called a \(GB_1^{**}\) -matrix, is proposed, and also the relationship between \(GB_1^{**}\) -matrices and other subclass of P-matrices is analyzed.