The invention relates to an automatic detection method for a narrow-band power carrier module of a three-phase power meter. The automatic detection method sequentially comprises the following steps that (1) feeding is conducted; (2) the module sequence and all products in a turnover box are detected, and if defective products are detected out, the positions of the defective products are marked; (3) a whole box is conveyed to a discharging conveying line after module detection is completed; (4) after a next box arrives, a manipulator grabs the defective products, qualified products are supplemented for the box until the box is full, and then the transfer box full of the products is conveyed to a stacking machine; and (5) after the stacking machine reaches the set stacking number, a storagedischarging system conveys the module back into a storehouse for storage. The method fills in the gaps of national carrier module metering, automatic production, warehouse logistics and testing, the carrier replacement time of procedures can be shortened, time waste caused by equipment wire change is avoided, the cost of detection equipment is greatly reduced, the space utilization rate is increased, the procedures of discharging the module out of the box and feeding the module into the box are avoided, manual participation is reduced, and the product detection efficiency can be greatly improved.