本文通过研究离散型严格正实矩阵G(z)=C(zI-A)~(-1)B+D 的 Roubust 性质,进而得到了离散型严格正实引理,即有理分式矩阵 G(z)=C(zI-A)~(-1)B+D 是严格正实的充分必要条件:存在对称正定矩阵 P和Q,以及矩阵 W和 L,使得 ATPA-P=-LLT-Q,ATPB=CT-LW,WTW=D+DT-BTPB In this paper, we study the Roubust property of the discrete strict positive real matrix G (z) = C (zI-A) -1 (B + D), and then obtain the discrete strictly positive real lemma, ie the rational fractional matrix G The necessary and sufficient condition for strictly positive real existence is that there exist symmetric positive definite matrices P and Q and matrices W and L such that ATPA-P = -LLT-Q, ATPB = CT-LW, WTW = D + DT-BTPB