The method includes following steps: based on signal of incoming call outside, the incoming call response circuit generates interrupt signal; CPU responds to the interrupt signal, and handset collectsand measures ambient sound; comparing with result collected and measured, and based on operation configuration setup by user in advance, CPU sets operation for ring volume; CPU sends data of ring toD/A converter to control speaker sounding or other operation of prompt mode. Based on measured result, handset can adjust ring volume or other prompt method. Based on own habit, user can carry out flexible configuration in order to suit to different situation. Features are: easy of use and stable operation.