The Altar of Prayer for Grain Complex was the place for Heaven-worshipping in the first lunar month in the Ming and Qing dynasties. Among them, the Hall of Prayer for Good Harvests and the Altar of Prayer for Grain were places of sacrificial activities. The east and west side halls within the Gate of Prayer for Good Harvests were places for restoring the sacrificial tablets.

The Altar of Prayer for Good Grain, a three-tiered round white-marble sumeru pedestal, is at the courtyard’s center by the north. It is encircled by a white-marble balustrade. On top of the Altar of Prayer for Good Grain is the Hall of Prayer for Good Harvests. It is round in plan with a three-eave conical roof topped with a gilded copper roof crown. Four longjing pillars, representing the four seasons, support the top eave of the hall. Outside the four pillars are 12 jin pillars supporting the second-level eave, symbolizing the 12 months. Other 12-eaved pillars further outside support the third-level eave to signify the 12 shichen (one shichen equals two hours) of a day.