| Five full-scale knee joints of concrete frame with HRB500 reinforcements were designed，and pseudo static tests were conducted. Seismic performances of two new kinds of precast knee joints were investigated. Failure patterns, hysteretic loops, skeleton curves, displacement ductility, energy dissipation capacity, and ultimate bearing capacity were analyzed. Besides, the calculation method of bending bearing capacity of inclined section in knee joint were proposed. The results indicated that all the precast specimens were subjected to bending failure in the small range of the beam end. There was no crack on the combined interface of frame beams. Compared to the cast in situ joint, the precast joints had a greater displacement ductility coefficient and the hysteretic loops were chubbier. The displacement ductility coefficient and ultimate displacement angle of precast joints were from 2.54 to 3.66 and 1/29 to 1/26 respectively. The ductility of specimens without extended column head were greater than that of specimens with extended column head. The average ultimate bearing capacity of precast specimens was about 10% lower than that of the cast in situ joint, while the ratio of calculation value to experimental value was from 0.62 to 0.71, still having a high safety degree.