Abstract: The design theories and dam construction technologies of concrete faced rockfill dam with the height of more than 300 m in China have reached the advanced world level at present. But the traditional measuring methods are not suitable for the safety monitoring of the high concrete face rockfill dam, and the new techniques for safety monitoring of high concrete face rockfill dam are needed. Tests on the proposed technology for horizontal displacement monitoring the dam by using distributed optical fibers are performed through model tests with 1:1 scale and prototype tests. The test result show that the new technology for horizontal displacement monitoring the dam can be used to measure the inner deformation of the dam 300 m in height with the measurement line 1000 m in length. Its measurement accuracy is verified by both the model and the prototype tests, and the relevant regulatory requirements are satisfied. It can meet the work requirements for the internal horizontal displacement monitoring of high concrete face rockfill dam. Applications in internal horizontal displacement monitoring of embankment dam show that the new technology has unique characteristics and advantages, it is good prospect.