The clock tower's main structure comprised three levels. The upper level bore an armillary sphere, used for astronomical observations; on the middle level was a celestial globe, which displayed the movements of celestial bodies; while on the bottom level were wooden mannikins which struck the time of day. The whole formed "a single mechanism, turned by the power of water, without human effort."
它的主結構共有三層，上層是用來觀測天文的「渾儀」，中層是演示天體運行的「渾象」，下層是報告時辰的「司辰」，全部「貫以一機，激水轉輪，不假人力」。