The control method includes following steps: (1) in a call between calling party and called party, through registering basic call event, service control point informs dual-tone multifrequency (DTMF) signal needed to monitor to service switch point; (2) service switch point monitors telephone channel; when registered DTMF signal occurs in telephone channel, service switch point makes report to service control point. Comparing with current intelligent network, the invention gets rid of limitation that users' information interaction is unable to carry out in calling procedure so as to be able toobtain keying information from users. The invention raises flexibility of intelligent service, making intelligent service possible to interact to users. For example, in selected charging service, after off hook, called party pushes button # key to affirm paying charge, intelligent system can keep call between calling party and called party after receiving response from the called party.