The invention provides a method, a base station and a terminal for monitoring the communication mode and measuring signals, which are used for a long-term evolution time-division duplex system. The method comprises the following steps: transmitting a task for monitoring a predetermined communication mode and measuring the signals to a terminal on a downlink control channel; converting into the predetermined communication mode when a measuring time slot behind a downlink synchronous time slot arrives, monitoring the predetermined communication mode and measuring the signals in the measuring time slot through the terminal, and acquiring the monitoring and measuring result; and receiving the monitoring and measuring result reported by the terminal on an uplink control channel. The embodimentof the invention can conveniently realize the monitoring and measurement capabilities under the condition of LTE system switching on the basis of not influencing the prior functions, and strengthen the intercommunication and seamless roam capacities of the LTE TDD system.