In architecture the entire design is symbolic. The southern part of the Inner Temple is square, while the northern part is semi-circular, a pattern representing the ancient belief that Heaven is round and Earth square. The northern wall was built higher than the southern wall, illustrating the notion of Heaven surpassing Earth. Compared to the imposing complexity and intricacy of royal palaces, the altar area here is simple, setting off the vastness of the sky, and the grandeur of Heaven.

In ancient China, odd numbers were regarded as heavenly or as related to the sun. Since nine was considered the most powerful of all numbers, the altar, a three-tiered terrace, was constructed with rings of stone slabs in multiples of nine, and the steps and balustrades are also in multiples of nine. At the center of the top terrace lies a round stone known as the Center-of-Heaven Stone (Tianxinshi), which has an amplifying impact for speeches made from it.