LED device protection circuits and protection methods are provided. An exemplary LED device protection circuit includes a first comparator, a protection-signal generating circuit, a sampling-voltage acquisition circuit, and a first reference-voltage acquisition circuit. The first comparator is connected with the sampling-voltage acquisition circuit and the first reference-voltage acquisition circuit, respectively. The first comparator is further connected with the protection-signal generating circuit. The first comparator is configured for comparing a sampling voltage outputted from the sampling-voltage acquisition circuit with a first reference voltage outputted from the first reference-voltage acquisition circuit, and outputting a pulse signal in accordance with a comparison result to the protection-signal generating circuit for generating a protection signal when the pulse signal satisfies a preset condition. The protection signal is configured for turning off an output load connected to a dimmer.