The performances of two modes of digital broadcast signals in Digital Television Terrestrial Broadcasting(DTTB) standard applied in bistatic radar are analyzed and compared by ambiguity function, as well as their target resolution characteristics. The ambiguity functions of single carrier and multi-carrier of DTTB system are studied in different receiving angles. The relative positions of secondary peaks in bistatic ambiguity functions, and the causes of secondary peaks generation are obtained. The relative relationships of the secondary peak positions between the monostatic and the bistatic ambiguity functions are obtained as well. The velocity resolution and range resolution of DTTB in bistatic radar are analyzed, and two modes of signals exhibit approximately the same resolution while the single carrier DTTB signal has better resolution.