A composite pallet structure includes a unit pallet including: upper and lower basic supporting boards, at least two spaced-apart auxiliary rods attached to each of the corresponding sides of the upper and lower basic supporting boards, a plurality of spacers distributed between the auxiliary rods on the upper basic supporting board and the auxiliary rods on the lower basic supporting board, and a plurality of fixing elements for restricting the spacers within the space between the upper and lower basic supporting boards in order for the unit pallet to have high supporting strength. The composite pallet structure needs no soldering and, therefore, can be easily repaired and recycled.