The present invention provides a method and device for writing on a capacitive touch screen, which includes a guarding pattern and a conductive strip pattern exposed from each other, and a stylus. The conductive strip pattern includes a plurality of first conductive strips provided with a driving signal and a plurality of second conductive strips that provide mutual capacitive coupling signals, and the guarding pattern is provided with a DC signal. The stylus has a conductive pen head and a pen body. When the human body holding the pen body is not electrically coupled to the conductive pen head, the location of the conductive pen head can be determined by sufficient change in capacitive coupling caused by the conductive pen head capacitively coupling to the guarding pattern and the conductive strip pattern.