Let Ω be a bounded pseudoconvex domain in Cn with smooth boundary. The purpose of this paper is to give another proof of the following well known Kohn's global regularity theorem: THEOREM. Suppose that a ∈C∞ (0, q) (Ω) is a smooth (0, q) -form with ∂a = 0. Then there is a smooth solution v ∈C∞ (0, q-1) (Ω) to the equation ∂v = a. The proof proceeds for the most part along the proof of Kohn[5]. Instead of the estimate obtained by Kohn[5], we use the estimate obtained by Catlin[1].