A lie down on the want to urinate may be mental psychological factors, acute cystitis, bladder stones and other factors lead to. 1. Psychological factors: when lying down to rest, due to the fear of increasing the number of urination at night, may be more psychological tension or anxiety, easily induced by psychogenic urinary frequency, there will be frequent urination, after adjusting the psychological state can be improved on their own. 2. Acute cystitis: may be related to the lack of attention to hygiene, when the infection is aggravated, it will make the bladder mucosa sensitivity is too high, when lying down, there is a small amount of urine on the sensitive parts of the stimulation, there will be urine, accompanied by pain in urination, urinary urgency and other symptoms. 3. Bladder stones: may be secondary to kidney stones, may also be too little water, the body metabolic abnormalities and other factors related to, when lying down, due to changes in body position, the stones move, causing stimulation of the bladder, it will cause frequent urination, also accompanied by urination difficulties, urination pain, hematuria and other symptoms. Lying down to urinate may also be caused by other factors, if the patient is lying down to urinate for a long time and accompanied by other obvious abnormalities, should be alert to disease factors, it is recommended to go to the regular hospital for medical treatment.