Abstract: The present invention provides a system for continuously producing diethyl methylphosphonite, comprising a rapid mixing reactor and a material circulation subsystem. An inlet of the rapid mixing reactor is provided with a rapid mixing component; the rapid mixing component comprises a first liquid inlet and a second liquid inlet: the second liquid inlet is used for feeding a material containing methylphosphonous dichloride; the material circulation subsystem comprises a filter, a material distribution unit, an acid binding agent premixer and a heat exchanger, which are connected in sequence; the filter is also provided with a solid waste outlet; the material distribution unit is also provided with a diethyl methylphosphonite outlet; the acid binding agent premixer is also provided with a reaction raw material inlet and an acid binding agent inlet; an inlet of the filter is connected to an outlet of the rapid mixing reactor; and an outlet of the heat exchanger is connected to the first liquid inlet.