Several formulas for calculating compression strength of corrugated cartons were introduced. Compression tests of different cartons were carried out according to national standards; the compression strength was calculated and the results were compared. The results showed that as long as the cartons fulfill one of the three conditions, the height is 400 mm, the length-width ratio is around 1.6, and the overall dimension is around 1600 mm, the cartons have the better compressive property; the calculated results have little practical meaning except Kellicutts'. It's considered to be necessary to take the optimal size as one of the factors for design and production.