Abstract: Let T be a formal triangular matrix ring, where A and B are rings and U is a(B, A)-bimodule. A characterization of Gorenstein FP-injective left T-modules over the formal triangular matrix ring T is given. Moreover, the Gorenstein FP-injective dimension of a left T-module is discussed.

Key words: Gorenstein FP-injective left T-module, left GFPI-closed ring, Gorenstein FP-injective dimension