A method and a device for measuring the gravity gradient of pyramid-like atomic interference based on two-dimensional cross gratings are provided. The method comprises the following steps: S1, preparation of a cold atomic group: a cold atomic group is obtained through pre-stage cooling; S2, velocity selection and state preparation: the temperature of the atomic group further decreases through Raman velocity selection, and a state is prepared on a magnetically insensitive state |F=1, mF=0>; S3, atomic interference: PI/2, PI and PI/2 light pulses are applied to the atomic group through two beamsof Raman light to realize the splitting and combining of the atomic group, and an atomic interferometer is constructed; and S4, internal state detection: after interference, the atomic group falls freely for a period of time, the number of atomic populations at a hyperfine energy level in two ground states is measured through the effect of probe light, pump light and astigmatic light, and the transition probability and the gravity acceleration value are finally obtained. The device is used to implement the method. The method and the device have the advantages of small overall size, strong robustness, low cost, high measuring accuracy, and the like.