Lying down easy to urinate frequently, may be related to physiological factors, psychological factors, bladder disease and so on. 1.Physiological factors: (1) When you drink too much water before lying down, it can cause frequent urination easily after lying down. (2) It may also be due to an increase in the volume of return blood after lying down, resulting in an increase in the cardiac output per beat, an increase in blood pressure, an increase in afferent nerve impulses to the pressure receptors in the aortic arch, which in turn inhibits the sympathetic constrictor nerve, causing vasodilation, an increase in renal blood flow, an increase in filtration, an increase in the production of urine, and the production of frequent urination. (3) lying down, physical and mental relaxation, parasympathetic nervous tension increases, amplifying the feeling of wanting to urinate. 2. Psychological factors: when the patient has anxiety, nervousness, insomnia, after lying down, he is always worried that he will be woken up by urine at night, so he wants to urinate as soon as he lies down. 3. Bladder diseases: such as overactive bladder disease, there will be frequent urination, urinary urgency, increased nocturia and other symptoms. When patients with such symptoms, the symptoms are serious, they should go to the hospital as soon as possible, to clarify the cause of the disease, and receive regular treatment as soon as possible.