The present invention discloses a light emitting device open/short detection circuit, which is used for detecting at least one light emitting device string open/short. Each light emitting device string has a first end and a second end, wherein the first end is coupled to a voltage supply circuit to supply electrical power to the light emitting devices. The open/short detection circuit includes: an abnormal voltage detection circuit coupled to the light emitting device strings for receiving voltages of the second ends respectively and generating an abnormal voltage detection signal; a voltage setting circuit coupled to the abnormal voltage detection circuit for setting an abnormal reference level; and a determination circuit coupled to the voltage setting circuit. When the abnormal voltage detection signal is equal to or over the abnormal reference level, the determination circuit generates an open/short detection signal for an abnormal condition detected.