A method for dynamically adjusting a Bluetooth connection interval applied to an ECG measuring instrument includes: S1. initializing a Bluetooth module in a slave machine of the ECG measuring instrument, which enters an executable working status after self-inspection; S2. setting a Bluetooth system connection status based on a system status marking event sent from the slave machine to a master machine; S3. according to the connection status determined in step S2, the master machine and the slave machine entering a low-speed connection status after they complete data transmission in a high-speed connection status; S4. implementing interrupt processing between the master machine and the slave machine if no data transmission occurs between the master machine and the slave machine over 2 ms; and S5. going back to step S2 if the connection needs to be restored.