Hazardous materials transportation vehicles may become one of the main attack goals under the background of terrorist attacks. This article gives an optimisation method of emergency service facility location for a specific counterterrorism area. Firstly, the multi-objective optimisation model of emergency service facility location is proposed through maximising cover risks, minimising emergency response time, emergency facilities fixed costs and transportation costs. Secondly, the model is solved with an improved genetic algorithm, which use 0-1 encoding method to code chromosome, use roulette with the optimal preservation strategy to conduct choose operation and use adaptive weighted distribution method to assign weight. Finally, a case study with 12 nodes and 21 roads is given to indicate that the optimisation model and algorithm are feasible.