In the underdetermined model Ŷ = AX + N, where X is a K-group sparse matrix (i.e. it has no more than K non-zero rows), the matrix A may be also perturbed. Theoretically, a more relaxed condition means that fewer measurements are required to ensure sparse recovery. In this study, a relaxed sufficient condition is proposed for greedy block coordinate descent (GBCD) under total perturbations based on the restricted isometry property in order to guarantee that the support of X is recovered. We also show that GBCD fails in a more general case when 1/(K + 1) ≤ δ K + 1 < 1. A′ denotes the transpose of A, and x i is the ith row of X. The cardinality of a finite set Γ is denoted by |Γ|. Let Ω := {1, 2, …, n}, Γ c = Ω∖Γ = {i | i ∈ Ω, and i ∉ Γ}. The support of X is denoted by supp(X) (supp(X) = {i | x i ≠ 0}). ∥ A ∥ 2 (K) denotes the largest spectral norm taken over all K-column submatrices of A. ∥ ⋅ ∥ F denotes the Frobenius norm. I d ∈ ℝ d × d is an identity matrix. The