Aiming at the low power consumption, bluetooth low energy (BLE) connection delay, and narrow band internet of things (NB-IoT) downlink traffic response delay requirements for NB-IoT and BLE dual-mode single-standby terminals, a terminal communication control method based on semi-Markov chain is proposed to enhance the comprehensive performance of the terminal. By integrating the extended idle mode discontinuous reception (eDRX) and power saving mode (PSM) of NB-IoT, where radio frequency is exclusively dedicated to BLE in PSM, a semi-Markov chain model for terminal communication state transition is constructed. This model is used to derive the power saving rate and the calculation model for the average NB-IoT downlink delay. Based on the delay requirements of BLE connection and NB-IoT downlink traffic, and combined with NB-IoT real-time traffic data, the critical parameters of eDRX are dynamically calculated. Subsequently, the terminal optimal comprehensive performance is achieved through optimizing BLE broadcast duration. Experimental results show that the proposed method achieves a power saving ratio exceeding 0. 96 in low-power demand scenarios. Furthermore, in low-delay demand scenarios, the average downlink traffic response delay is less than 10 seconds. This method satisfies the communication delay requirement and reduces the communication power consumption of the terminal.