The present invention relates to a method for designing paint drying for a closed area (CA), the method comprising: a first step (S10) of inputting basic design information on the closed area (CA); a second step (S20) of setting a plurality of air supply design proposals for the closed area (CA); a third step (S30) of comparing air circulation performance regarding the air supply design proposals; and a fourth step (S40) of deriving a final air supply design proposal by repeating the first to third steps (S10 to S30). Accordingly, it is possible to optimize a location of an air supply or ventilation device so as to improve air circulation within the closed area by utilizing a simulation technique based on CFD in relation to a painting work of a closed block of a large vessel. [Reference numerals] (S10) Input basic design information; (S20) Set a plurality of air supply design proposals; (S30) Compare air circulation performance; (S40) Derive a final air supply design proposal
