Abstract: The Henglong mountain tunnel of Fulong Expressway was constructed by New Austrian Tunneling Method(NATM). This article not only introduced the monitoring and measuring technology of construction on displacement of surrounding rock and the change of stress by mouth of a horn part of the super large section in the Henglong mountain tunnel, but also introduced the timely adjustment of supporting system design parameters such as tunnel prestressed rock bolt according to the monitoring and measurement analysis of treatment results in this project. Results showed that careful monitoring and analysis of the construction work play a key role not only in ensuring the tunnel construction safety and the economic and reasonable supporting, but also in obtaining reliable design parameters.