The utility model relates to a transmitting apparatus for in-band on-channel digital-analog audio frequency broadcast signals, comprising a simulation sound modulation module, a digital signal modulation module, a hybrid module, a digital analog converter, an upper transformation module, a power amplifier and an antenna feed system. The digital modulator of the digital signal modulation module generates digital signals and copies the digital signals in adjacent signal frames; the hybrid module comprises an adder and a subtracter, the values of the simulation sound broadcasting signals in adjacent signal frames *2m, *2m+1 are respectively added and subtracted by dm to obtain the digital-analog mixing signals the simulation sound broadcasting signals in adjacent signal frames *2m-dm, *2m+1+dm, which are transmitted in the same broadcast channel. According to the utility model, the digital-analog mixing signals with completely overlapped frequency spectrum are obtained, the frequency band is saved, and the complete separation of digital-analog signals at a receiving end is promoted.