In order to popularize the structure form consisting of the compostite beam and the compound spiral hoop-reinforced concrete (CSHRC) column,a beam-through-type connection of the castellated composite beam- CSHRC column is proposed.In the core zone of the connection,the U-shaped stirrups cross the beam web,while the short steel plate hoops of column are set at the beam top and the bottom flanges position.Through the low-cycle reversed loading experiments of two 1/2-scaled castellated composite beam-CSHRC column connection specimens and a simulating core zone specimen,it is found that the local buckling failure of the steel beam occurs near the column face for the specimen with an expansion ratio of 1. 2 while near the column face and the web opening for the specimen with an expansion ratio of 1. 3.Moreover,a formula of the shear capacity of the connection core zone is put forward,and the calculating values based on the formula accord well with the experimental ones.The two 1/2- scaled connection subassemblies both have an ideal spindle shaped load-drift hysteresis curve,and their ductility factors and equivalent viscous damping coefficients are respectively 4. 55,4. 30 and 0. 46,0. 38,which means that the proposed connection has a good anti-seismic behavior.