It is significant to adopt the multi-mode fiber as the transport media instead of single-mode fiber in a white-light interferometer. The use of the multi-mode fiber can improve system sensitivity and reduce system cost. In this paper, we investigate theoretically and experimentally the characteristics of interferometric signals of a white-light interferometer employing multi-mode fibers as transport media and a broadband laser diode as light source. And point that the relative large intensity ratio of three interferometric regions caused by the use of multi-mode fiber has no great disfavor for the determination of the central fringe.