Accounting for the excavating effects of the Yongjiu road tunnel in the Beigan Mountain on adjacent existing civil air defense works,the method of monitoring the works during the highway tunnel construction using drill blasting method was studied in order to establish a more robust method of monitoring.The method is mainly concerned with the selection of monitoring equipment,the warning value,the frequency of monitoring,the positioning of monitoring points,etc.The surrounding rock deformation and pressure change of roadway floors were analyzed to show the feasibility and reasonableness of the monitoring method.