Abstract: To study influence of construction joints and cast-in-place floors on the "strong column and weak beam" for RC plane frames, horizontal low-cycle repeated tests were conducted on three RC plane frames with one story and two spans, the failure modes and hysteresis curves of each specimen were analyzed. The results showed the plane frame with construction joints at beam ends failed due to plastic hinges at beam ends, and the plane frame with the cast-in-place floors failed due to plastic hinges at column ends; the construction joints at beam ends reduced the integrity of frames, which were more prone to the "strong column weak beam". The aseismic performances of structures were poorer; cast-in-place floors could enhanced the bearing capacity of frame beams, including the yield loads, ultimate loads and corresponding displacement of structures, and increased the structural energy consumption.