A convenient self-locking blood pressure cuff facilitating one-handed use by a user taking his own blood pressure includes a cuff belt, a casing assembly, and a self-locking structure. The self-locking structure is received in the casing assembly. The self-locking structure includes a core shaft, a locking assembly, and a pressing assembly. The core shaft is slidably connected to the casing assembly. The locking assembly and the pressing assembly are wrapped around the core shaft. The locking assembly can rotate when a free end of the cuff belt moves with respect to the casing assembly. The locking assembly can further press against the cuff belt when the core shaft slides in the casing assembly. The pressing assembly presses against the locking assembly to prevent the locking assembly from rotating back.