The utility model provides a splicing tube for a 1000kV alternating-current extra-high-voltage expanded conductor with double circuits on a same tower. The splicing tube is characterized in that the splicing tube comprises an aluminum tube with the inside diameter larger than or equal to the outside diameter of the expanded conductor to be connected, and a steel core connecting component fixed inside the aluminum tube in an embedded way and used for connecting a steel core of one expanded conductor with a steel core of another expanded conductor. The steel core connecting component is configured in the center of the aluminum tube. The splicing tube aims at solving the technical problem of meeting the strict requirement on environment protection in a 1000kV extra-high-voltage transmission line with double circuits on the same tower. By adopting the way of the splicing tube, the total weight of the conductor and the number of split conductors are greatly reduced, the load and the structural weight of the iron tower are reduced, and the investment in the line is remarkably reduced, therefore, the splicing tube has remarkable economic benefit and social benefit.