The invention discloses a brand new oral solid medicinal composition and its preparation method, the medicinal composition is an oral preparation prepared by hydrochlorothiazide, levamlodipine, losartan potassium and pharmaceutically-accepted auxiliary materials, the oral preparation is including but not limited to tablets or capsules. The composition comprises the following raw materials by weight part: 5-25 parts of hydrochlorothiazide, 2.5-5 parts of levamlodipine, 20-120 parts of losartan potassium, 30-90 parts of lactose, 20-60 parts of microcrystalline cellulose, 20-60 parts of pregelatinized starch, 2-5 parts of hydroxypropylcellulose, 1-3 parts of silica and 1-2 parts of magnesium stearate. The medicinal composition has the advantages of scientific and reasonable prescription, lowauxiliary materials content and high biological availability, and is a preferred medicine for treating hypertension.