Abstract: To study the adaptability of cosmonauts to the acoustic environment in the orbit cabin of a spacecraft during the depressurization & repressurization courses, the simulation tests in the KM6 horizontal cabin were carried out. The measurement results of the tests and the actual feeling of cosmonauts show that the acoustic environment in the orbit cabin during the depressurization & repressurization courses can meet related requirements of not causing harmful effects for cosmonauts during spaceflight.