This paper presents the use of Acoustic Emission Technique (AE) to evaluate the fracture behavior of different RC slabs under the load test. During the load test, AE inspection was applied using a self-developed instrument to record/monitor the emitted ultrasonic waves within the 2 X 2 m slab-type specimens. AE records for three RC slabs were demonstrated here for analyzing in hit-count, frequency and wave-form. These results revealed the ”Kaiser effect” and the ”intermittent” characteristic due to the concrete-rebar mechanism and other composite behaviors.