多带图灵机和图灵机类似，唯一的不同在于它可以有 条纸带，每条纸带上 都有一个读写头。其状态转移函数 修改为：

此处 是带子的数目。表达式

其中 = L 或 R， 说明若机器处于状态 ， 读写头 所读出的符号分别为， 则转移到新状态 ， 将读写头 下的符号分别修改为 ， 并将读写头 按照 所指示的方向移动， 读写头 向左移， 读写头 向右移。

A Multi-tape Turing machine is like an ordinary Turing machine with several tapes. Each tape has its own head for reading and writing. Initially the input appears on tape 1, and the others start out blank.

This model intuitively seems much more powerful than the single-tape model, but any multi-tape machine, no matter how many tapes, can be simulated by a single-tape machine using only quadratically more computation time. Thus, multi-tape machines cannot calculate any more functions than single-tape machines, and none of the robust complexity classes (such as polynomial time) are affected by a change between single-tape and multi-tape machines.