Abstract: The bore assignment of the multi-joint tunnel-drilling robot is stochastic sequence; the bore planning is very difficulty. The application of genetic algorithm to bores planning of the multi-joint tunnel-drilling robot is discussed in this paper, we introduce the direction change of every robot joint from three contiguous bores as numerical value, adopt numerical value "0" to describe the difference movement trend and "1" consistent trend, and can modify the numerical value on the foundation of the fact condition, then present an adaptation function on the basis of the change trend of joint. Simulation shows that applying this adaptation function can find out the global optimal solution and obtain fast convergence velocity. As a result, the conclusion can be satisfied with the need of work. This method can be effectively used for reference to other multi-robot system.