The estimation on the inverse elements of strictly diagonally dominant tridiagonal matrix is established; in this estimation, the nonnegative condition of matrix elements is moved.

Generalized strictly diagonally dominant matrices play an important role in many fields, but it isn't easy to determine a matrix is a generalized strictly diagonally matrix or not.

In this paper we propose the concept of a weak strictly diagonally dominant matrix given some DE terminate sufficient conditions for generalized strictly diagonally dominant matrices.