The invention discloses a method for breaking away a continuous wall and a side all at the joint of new and old metro stations. The method comprises the following steps that A, the positions for cutting the underground continuous wall and the side wall at the joint of the new and old metro stations are determined; B, a hoisting hole and a rope passing hole are drilled; C, a guide pulley and wire sawing equipment are mounted and fixed; D, a diamond rope is mounted, and the diamond rope penetrates through the rope passing hole; E, a hoisting rope penetrates through the hoisting hole; F, an operation system is chained, and a safe guardrail is mounted; G, the walls are cut in sequence; and H, hoisting and smashing are conducted. Through the method, the continuous wall and the side wall of thenewly built metro station and the existing metro station can be broken away safely and efficiently, the construction period can be shortened by utilizing the method to conduct underground engineeringconstruction, the construction noises are reduced effectively, dust is reduced, and the construction safety, the safety of the existing structure, the metro operation and the passenger safety are ensured.