The invention relates to a pharmaceutical composition for treating constipation and an application method thereof and belongs to the technical field of traditional Chinese medicine. The pharmaceutical composition is prepared from, by weight, 20-25 parts of semen cassiae, 20-25 parts of fructus lycii, 15-20 parts of radix astragali, 15-20 parts of cistanche salsa, 10-15 parts of semen armeniacae amarae, 10-15 parts of radix glycyrrhizae, 15-20 parts of fructus cannabis, 10-15 parts of semen platycladi, 15-20 parts of radix paeoniae alba, 10-15 parts of fructus aurantii immaturus, 10-15 parts of poria cocos, 15-20 parts of semen pruni, 5-10 parts of radix ophiopogonis, 10-15 parts of radix scutellariae and 200-300 parts of honey. The pharmaceutical composition for treating the constipation has the advantages that the pharmaceutical composition is simple in preparation process, and the medicinal materials are combined to achieve synergic effects of tonifying the spleen and qi, relieving stagnant qi and removing food retention, clearing away heat and drying dampness, relaxing bowel, increasing human body internal immune function, enhancing body resistance, improving blood circulation of organs and tissue close to the colon and relaxing bowel without body fluid impairment; the constipation can be treated radically, and side effects are avoided; the pharmaceutical composition has a good assistant treatment effect on the constipation caused by endocrine dyscrasia, insomnia, dreaminess, fatigue and presenility and is especially suitable for middle-aged and aged patients.