The invention discloses a method for obtaining a Ramsey-CPT spectrum. The method includes the steps that a current periodically switched between I<1> and I<2> is coupled with microwaves to be input into a laser tube, wherein when the laser tube works with the current I<1>, the power of a positive first-stage sideband and the power of a negative first-stage sideband in polychromatic light output by the laser tube are maximum, and the frequency meets the requirement for CPT resonance with alkali metal atoms; after the current is switched, the jumping probability of all frequency components of the polychromatic light output by the laser tube and the alkali metal atoms is almost zero. In this way, the alkali metal atoms are switched between the state of being acted with lasers to generate CPT resonance and the interaction-free free relaxation state, and therefore Ramsey-CPT interference is generated. The invention further discloses a device for obtaining the Ramsey-CPT spectrum. By means of the scheme, a Ramsey-CPT atomic clock which is the same as a fashionable CPT atom clock in size and power consumption and better than the fashionable CPT atom clock in frequency stability can be achieved.