Under the assumption of nonexistence of the jump-mode, this paper gives a standard form of a large class of 2-D singular systems. This class of systems includes all the systems resulted from the linear state transformations of 2-D singular Roesser models and hence we called it the extended singular Roesser models. The criteria are presented for testing that via some suitable invertible linear state transformations, the given 2-D singular systems in the extended Roesser models can be converted equivalently to the classical Roesser models. Some results on 2-D classical singular Roesser model such as the reduced order regular observer and compensator design can be hence generalized to the extended models.