
According to this great article about the symbolism of old Chinese communist outfits, "...popular mythology assigned a revolutionary and patriotic significance to the Sun Yat-sen (the suit's designer) suit, even though it was essentially a foreign-style garment. The four pockets were said to represent the Four Cardinal Principles cited in the classic Book of changes and understood by the Chinese as fundamental principles of conduct: propriety, justice, honesty, and a sense of shame. The five centre-front buttons were said to represent the five powers of the constitution of the Republic and the three cuff-buttons to symbolise the Three Principles of the People: nationalism, democracy, and people's livelihood".
Like Che t-shirts and Adidas CCCP Originals however, the Mao suit is no longer a symbol of the communist revolution, it has become a design icon, as demonstrated by the work of Chinese artist Sui Jianguo. See below this series of bright colored Mao suits.

(via "I see what you mean". By the way, doesn't it sound like a cousin of "Just Trying to Understand"? Funny.)