The invention discloses a method for fully automatically producing a bed core, which comprises: step 1, coiling steel wires into springs, and outputting the springs at equal intervals; step 2, adjusting the springs to upright conveying, then positioning the springs, arraying the springs into groups, and then automatically pushing the springs to a string spring position; and step 3, stringing the springs into the bed core by string spring steel wires. The invention also discloses a device for fully automatically producing the bed core, which comprises an automatic spring coiling machine, an automatic string spring assembling machine, an automatic feeding machine and a complete machine control device. The automatic spring coiling machine is provided with a step output mechanism. The automatic feeding machine is provided with a turnover mechanism, a transmission mechanism and a positioning push mechanism. The turnover mechanism is connected with the step output mechanism and simultaneously connected with the transmission mechanism. The positioning push mechanism comprises a position sensor, a plurality of positioning plates and a plurality of push plates. The automatic string spring assembling machine is placed on the transmission mechanism of the automatic feeding machine in parallel. The complete machine control device is connected with the position sensor. The method and the device can achieve full automatic production from the steel wires to the bed core, and have high efficiency.