Abstract: The construction of underground cave group is very complex, with many operation surfaces, drilling, blasting, slag loading, transportation, injection anchor support and other process cross operation. The harmful gas such as blasting gas, exhaust from construction machinery and dust of concrete operation is produced in the construction, and the problem of ventilation and dust prevention is very prominent.Good construction ventilation is not only a necessity for labor safety, but also an important guarantee to create good construction environment conditions, improve work efficiency and speed up the construction progress. The structural characteristics of the underground tunnel group and the complexity of the construction process determine the particularity of the ventilation problem of the underground tunnel group.