The invention discloses a track circuit for signal superposition and an achieving method. According to the method, a pulse signal superposition branch circuit and a frequency shift signal superposition branch circuit which are connected in parallel are included, the pulse signal superposition branch circuit comprises an inductor-capacitor parallel connection circuit, and the frequency shift signalsuperposition branch circuit comprises a series resonance circuit. Cab signal code sending, steel rail occupation examination under the poor branch circuit condition, broken track and broken line examination, insulation breakage examination, branch parallel connection jumper and broken line examination and other functions can be achieved, and various problems existing in the aspect of transmission security of an existing in-station track circuit are solved.