The present invention relates to a door latch system, more particularly to a door latch system which includes: a stopping lever unit rotatably installed in the main locking member; a stopping threshold formed in the sub-locking member wherein a stopping protrusion is being caught; and a locking plate slidingly installed in a housing for rotating the stopping lever unit, wherein a lever guide portion is formed in the locking plate, and a guide bar is formed in the stopping lever unit, so that the rotation of the stopping lever unit is accomplished as the guide bar is guided by the lever guide portion, and the stopping lever unit can be coupled to or separated from the stopping threshold in accordance with sliding of the locking plate.