Early stage of Alzheimer’s disease is often accompanied by spatial structure function and executive function decline, by simply drawing a clock, it can detect the reconstruction ability of the elderly visual memory graphics, action planning and executive function, anti-interference ability. Data show that the accuracy rate of drawing a clock to test dementia is 80%~90%, and it has been widely used in foreign countries to screen for cognitive impairment in dementia patients. 1, draw a closed circle (dial), 1 point; 2, the number will be placed in the correct position on the dial (all the numbers are in the circle), 1 point; 3, in order to fill in the 12 numbers on the dial correctly, 1 point; 4, the hands will be placed in the correct position (whether there is an arrow on the hands, whether the minute hand is longer than the hour hand, etc.), 1 point. Drawing clock test scored 4 points for normal, 3 points for basically normal or mild dementia, 2 points for more than moderate dementia, 2 points below is already to the severe.