Abstract: In order to timely and accurately find the roof separation information and relevant measures,it should be taken to prevent the roof falling occurred in the min e roadway,thus a real time monitoring should be conducted on the roof separation value. According to the optical fiber and grating sensing principle,a new type optical fiber and grating roof separation indicator was researched and developed. A calibration test was conducted on the roof separation indicator in a lab. The test and theory as well as the application analysis results showed the full optical fiber roof separation on- line monitoring system composed with the optical fiber and grating roof separation indica tors could have high measuring accuracy,good long term stabiity,long distance signal transmission,intrinsic safety and other advantages and would provide an effective me ans to the long term on- line monitoring of the roof separation.