In this note, uniform bounds of the Birman-Schwinger operators in the discrete setting are studied. For uniformly decaying potentials, we obtain the same bound as in the continuous setting. However, for non-uniformly decaying potential, our results are weaker than in the continuous setting. As an application, we obtain unitary equivalence between the discrete Laplacian and the weakly coupled systems.2010 Mathematics Subject Classification. Primary 47A10, Secndary 47A40. Key words and phrases. discrete Schrödinger operators, resolvents, limiting absorption principle.Corollary 1.2. Under the condition of Theorem 1.1 (i) or (ii), H = H 0 + λV is unitarily equivalent to H 0 for small λ ∈ R. Remark 1.3. For Theorem 1.1 (ii), we show stronger results in Proposition 3.4. For Theorem 1.1 (i), we also obtain stronger results: Uniform resolvent estimates in Lorentz spaces as in Proposition 3.3. Remark 1.4. In [9] and [20], the authors prove the absence of eigenvalues of H 0 +λV for small λ ∈ R if |V (x)| ≤ C(1 + |x|) −2−ε for some C > 0 and ε > 0 with d = 3 and V ∈ l d 3 (Z d ) with d ≥ 4 respectively. In [1], (1) is proved under stronger assumptions: |V (x)| ≤ C x −2(d+3) with d ≥ 3. Moreover, in [14], (1) is established for V ∈ l p (Z d ) with 1 ≤ p < 6/5 if d = 3 and 1 ≤ p < 3d/(2d + 1) if d ≥ 4. The authors in [14] also study the scattering theory of H 0 + V .