In order to solve massive data sort in digital library and dataware house, a new highly efficient algorithm based on serpentine tape, named STESort (serpentine tape external sort), is provided in this paper. Taking full advantage of the characteristics of serpentine tape, the STESort algorithm reduces the whole seek time on tapes compared with traditional 2-way merge tape sort algorithm. Besides increasing the efficiency of tape sort, the STESort algorithm prolongs the duration of tapes by reducing the times of tape header moving on tape surface. The theoretical analysis and the experimental results show that the STESort algorithm is more efficient than the traditional tape sort algorithms. The STESort is suitable for massive data sort.