The present invention discloses an end plate system for joining spun piles together comprises a top end plate (100) mounted at a bottom end of a first spun pile: and a bottom end plate (200) mounted at a top end of a second spun pile; wherein the end plates (100, 200) respectively have an interlocking surface that is formed with a plurality of segmental protrusions (110, 210) and segmental recesses (120, 220) arranged in an alternate configuration; characterized in that each segmental protrusion (110, 210) has a first radial interlocking profile (111, 211) and a second radial interlocking profile (112, 212) that extend towards the central portion of the end plates (100, 200); wherein the top end plate (100) and the bottom end plate (200) are mated by registering the segmental protrusion (110, 210) of one end plate to the segmental recess (120, 220) of another end plate and through a rotating movement about the central axis of the mated end plates (100, 200), a first interlocking joint (300) is formed by two adjacent first radial interlocking profiles (111, 211) in full surface contact, and a second interlocking joint (400) is created by inserting a pin (402) into a passageway (401) formed between two adjacent second radial interlocking profiles (112, 212).