An operation mechanism of a 2P2M electromagnetic residual current circuit breaker with overcurrent protection (RCBO), comprising a handle and a connection rod with one end linked to the handle, wherein the other end of the connection rod opposite to the end linked to the handle is linked to a contact lever; a first hinging and linking shaft with one end configured to be hinged to a housing of the circuit breaker is disposed in a middle part of the contact lever; a first latch hinged to one end of the first hinging and linking shaft is linked to one side of the contact lever; an end of the first latch intermittently abuts against and is linked to the contact lever, and a second latch hinged to the other end of the first hinging and linking shaft is linked to the other side of the contact lever opposite to the side linked to the first latch; the other end of the contact lever opposite to the end linked to the connection rod is provided with a second hinging and linking shaft; the side of the contact lever towards the first latch is linked to a first movable contact, wherein the first movable contact is hinged to an end of the second hinging and linking shaft and is intermittently linked to the first latch; a first reset spring linked to the first movable contact is sleeved on a position where the second hinging and linking shaft is hinged to the first movable contact; the side of the contact lever towards the second latch is linked to a second movable contact, wherein the second movable contact is hinged to the end of the second hinging and linking shaft and is intermittently linked to the second latch; a second reset spring linked to the second movable contact is sleeved on a position where the second hinging and linking shaft is hinged to the second movable contact; and a relative linkage structure is disposed between the first latch and the second latch; and characterized in that the relative linkage structure comprises an insertion pin disposed on a side of a middle part of the second latch towards the first latch; the first latch is provided with a linkage shaft hole that fits with the insertion pin; and the contact lever is driven by the connection rod to push the first latch to rotate around the first hinging and linking shaft, and the second latch follows the first latch through the insertion pin to rotate around the first hinging and linking shaft, wherein a side of the middle part of the second latch far away from the first latch is provided with a first push pin linked to a current leakage protection apparatus. the relative linkage structure comprises an insertion pin disposed on a side of a middle part of the second latch towards the first latch; the first latch is provided with a linkage shaft hole that fits with the insertion pin; and the contact lever is driven by the connection rod to push the first latch to rotate around the first hinging and linking shaft, and the second latch follows the first latch through the insertion pin to rotate around the first hinging and linking shaft, wherein a side of the middle part of the second latch far away from the first latch is provided with a first push pin linked to a current leakage protection apparatus.