The invention is applied to the field of electronic illumination and provides a fluorescent lamp and an open circuit protecting circuit thereof. The open circuit protecting circuit of the fluorescent lamp comprises a rectifier filtering unit, a dividing unit and a half-bridge suppression unit. According to the fluorescent lamp and the open circuit protecting circuit thereof disclosed by the invention, a high-voltage direct current signal output by a self-exciting half bridge circuit of the fluorescent lamp is sampled, rectified and filtered by the rectifier filtering unit and is divided by the dividing unit for providing a trigger electrical signal for the half-bridge suppression unit; the triggered half-bridge suppression unit enters a work state to suppress the self-exciting half bridge circuit of the fluorescent lamp to work and enable the self-exciting half bridge circuit to stop oscillation, and thus the aim that the high-voltage electric shock risk is eliminated because no voltage is output from the output end of the self-exciting half bridge circuit of the fluorescent lamp when the fluorescent lamp is in open circuit or no fluorescent lamp body is connected is achieved.