A device for producing ethoxylation derivatives includes an assistant circulation loop with lower starting quantity is added on the base of the main circulation loop, and the assistant circulation pump is started first when slight chain initial dose is added with low flow rate of the ethylene oxide and high growth rate of polyreation; when the amount of reactant gets to the starting quantity of the main circulation pump, the main circulation loop is started with high flow rate of ethylene oxide. The two circulation loops cooperate with each other shorten reaction time and high yield in one batch; a pre-reaction cavity with smaller inner diameter than that of the main body of the reactor is extended from the bottom of the main body of the device, so that lower chain initial dose can start the assistant circulation pump, and then start the assistant circulation loop.