A hazardous chemicals truck-and-trailer transportation scheduling model with empty trailer task was established in an actual hazardous chemicals transportation network. The model involves two stages. In the first stage, an empty trailer scheduling plan with the shortest total distance was established. In this process, a scenario where a heavy trailer task unlocks an empty trailer was considered. In the second stage, a hazardous chemicals truck-and-trailer transportation scheduling model was established with the target to have minimum total operating cost and time consumption. Finally, a specific calculation example was established, and the programming was implemented using Microsoft Visual Studio 2013 development platform, to create hazardous chemicals truck-and-trailer transportation program. On comparing the truck-and-trailer transportation program with a program where there is no truck-and-trailer in hazardous chemicals transportation, it was seen that truck-and-trailer transportation program can reduce the number of the vehicles performing tasks by 50%, reduce total time consumption by 38% and total cost by 40.6%, which validates the effectiveness of the model and algorithm.