The paper considers the problem of observer design for discrete rectangular singular systems with time-delay. First, the observer design for discrete rectangular singular systems with constant time-delay is discussed. The system is described by the following form:where x(k)∈Rn is the state vector, u(k)∈Rp is the controlled input,y(k)∈Rq is the measurable output, z(k)∈Rl is the estimated output;E,A,Ad∈Rm×n,B∈Rm×p,C,Cd∈Rq×n,D∈Rq×p,L∈Rl×nare constant matrices, Eis a singular matrix, rankE =r0, d>0 is a known integer delay.To design an observer for system (2-1) as follows:such that for any admissible initial value it satisfies that At first, it is assumed that rankE = r |