We have developed a real-time (8~30 fps) photoacoustic (PA) imaging system with a linear-array transducer for burn diagnosis. In this system, PA signals originating from blood in the noninjured tissue layer located under the injured tissue layer are detected. The phantom study showed that thin light absorbers embedded in the tissue-mimicking scattering medium at depths of > 3 mm can be imaged with high contrast. The diagnostic experiments using rat burn models showed good agreements between the injury depths (zones of stasis) indicated by PA imaging and those by histological analysis. These results demonstrate the potential usefulness of the present system for clinical burn diagnosis.