In this note, some operator inequalities for operator means and positive linear maps are investigated. The conclusion based on operator means is presented as follows: Let Φ : B(H) → B(K) be a strictly positive unital linear map and h −1 1 I H ≤ A ≤ h 1 I H and h −1 2 I H ≤ B ≤ h 2 I H for positive real numbers h 1 , h 2 ≥ 1. Then for p > 0 and an arbitrary operator mean σ, (Φ(A)σΦ(B)) p ≤ α p Φ p (Aσ * B), where α p = max α 2 (h 1 ,h 2) 4 p , 1 16 α 2p (h 1 , h 2) , α(h 1 , h 2) = (h 1 + h −1 1)σ(h 2 + h −1 2). Likewise, a p-th (p ≥ 2) power of the Diaz-Metcalf type inequality is also established.