Quasi-static tests of six full-scale prestressed spun concrete square piles-cap connections were conducted to investigate the influence of 4 parameters on the seismic behavior of the connection.The results and findings indicate：①With axial load larger than 1 700 kN,failures governed by concrete compression take place in the connected part of the piles due to small eccentricity.②Axial load increases the loading capacity for the connection but on the other hand decreases its deformation capacity.The connection shows considerable deformation capacity under axial load of 1 700 kN.③Connection under diagonal loading condition is statically weaker,while showing better deformation capacity.④With a 50 mm dowel depth into the cap,the connection functions well and is capable of larger deformation.But the corresponding equivalent viscous damping coefficient is lower at failure.