A moving contact linkage structure for modular circuit breaker, comprising: a first case or and a second case, the first case or having a first mounting hole and the second case having a second mounting hole, a the position of the first mounting hole and the position of the second mounting hole corresponding to each other; a first shaft; an operation mechanism side plate, the operation mechanism side plate having a third through hole, the third through hole being positioned at a rotation center of a contact rotor; an operation mechanism lower connecting rod, the operation mechanism lower connecting rod having a fourth through hole, the first shaft connecting to the fourth through hole; a contact rotor, the contact rotor being rotatable around a rotation center, the contact rotor having mating surfaces on both sides; a first linkage member, the first linkage member connecting to the mating surface on a first side of the contact rotor, the first linkage member having a convex first axle at a position corresponding to the rotation center of the contact rotor, the convex first axle connecting to the third through hole; a second linkage member, the second linkage member connecting to the mating surface on a second side of the contact rotor; wherein the first linkage member, the contact rotor and the second linkage member are disposed in the first mounting hole on the first case and the second mounting hole on the second case, the first case and the second case are assembled to form a single phase contact module; the contact rotor and two second linkage members are disposed in the first mounting hole on the first case and the second mounting hole on the second case, the first case and the second case are assembled to form a further single phase contact module; and the single phase contact modules are adapted to be linked by directly connection linkage without any linkage structures independent to the contact modules. a first case or and a second case, the first case or having a first mounting hole and the second case having a second mounting hole, a the position of the first mounting hole and the position of the second mounting hole corresponding to each other; a first shaft; an operation mechanism side plate, the operation mechanism side plate having a third through hole, the third through hole being positioned at a rotation center of a contact rotor; an operation mechanism lower connecting rod, the operation mechanism lower connecting rod having a fourth through hole, the first shaft connecting to the fourth through hole; a contact rotor, the contact rotor being rotatable around a rotation center, the contact rotor having mating surfaces on both sides; a first linkage member, the first linkage member connecting to the mating surface on a first side of the contact rotor, the first linkage member having a convex first axle at a position corresponding to the rotation center of the contact rotor, the convex first axle connecting to the third through hole; a second linkage member, the second linkage member connecting to the mating surface on a second side of the contact rotor; wherein the first linkage member, the contact rotor and the second linkage member are disposed in the first mounting hole on the first case and the second mounting hole on the second case, the first case and the second case are assembled to form a single phase contact module; the contact rotor and two second linkage members are disposed in the first mounting hole on the first case and the second mounting hole on the second case, the first case and the second case are assembled to form a further single phase contact module; and