Defecation disorders is a common gastrointestinal disease characterized by slow colonic transit and/or paradoxical anal contraction. Gastrointestinal motility test plays an important role in the diagnosis, classification and treatment of defecation disorders. Anorectal manometry (ARM) provides comprehensive information about rectal and anal sphincter function, including resting anal sphincter pressure, squeeze anal sphincter pressure, the rectal and anal sphincter pressure changes during an attempted defecation, rectal sensory testing, rectoanal inhibitory reflex and rectal compliance. However, ARM can not diagnose the defecation disorders without the other tests. It should be combined with defecography and balloon expulsion test. Defecography demonstrates the anatomy and function of the anorectum and pelvic floor. Gastrointestinal transit test assesses regional and whole colon transit time. They are valuable methods in diagnosis of defecation disorders, but these tests have their respective advantages and disadvantages, and combined use should be carried out usually.