A meltblown composite production device formed by one-step molding relates to a production device of the nonwoven fabric, in particular to a composite production device formed by one-step molding of multiple meltblown filter materials. The production device comprises a rack, an automatic feeding device, screw extruders, spray nozzles, an air supply device, a receiving net, a suction device, a reciprocating trolley which can perform transverse reciprocating motion, a cloth-pressing roller, a balanced tension winding roller, an electret rack and a screw extruder automatic lift device, wherein the automatic feeding device contains a bin, a feeding pipe, a charging cylinder, a suction fan, a filter screen and a hopper; the number of the screw extruders is at least two, the outlets of the screw extruders are separately connected with spray nozzles; the spray nozzles are arranged on the outside of the receiving net, the inside of the receiving net, close to the position of meltblown fibers sprayed by the spray nozzles is provided with the suction device; the outside of the receiving net, close to the spray nozzles is provided with the electret rack, the receiving net is arranged on the reciprocating trolley; and the screw extruder automatic lift device contains a lifting drive motor, a speed reducer, a driving gear, a lifting screw, a guide post and a guide sleeve.