More attention has been paid to biochar which has been hot research area as a novel environmental functional material due to its special structure and physicochemical properties, it has multiple environmental benefits such as pollution remediation, soil improvement, carbon sequestration and emission reduction. The physicochemical properties of biochar were determined by the types and distribution of surface functional groups. Pyrolysis temperature and material type are two important factors affecting functional groups of biochar. In this article, animal manure biochars were prepared under different temperature from 200 ℃ to 700 ℃ with the materials of chicken manure, dairy manure and pig manure. On the basis of traditional one-dimensional infrared spectrum analysis, the change tendency of functional groups of animal manure biochars with the increase of pyrolysis temperature was revealed using the method of Fourier transform infrared spectroscopy (FTIR) combined with two-dimensional correlation analysis, providing a theoretical basis for better research on structure-activity relationship of biochar. The results showed that with the increase of pyrolysis temperature, Which variations mainly existed in the unceasing weakening of alcohols and phenols —OH peak and aliphatic —CH₂ peak of manure biochar, among which the changes of chicken manure were the most obvious. Furthermore, the changing intensity of —OH was higher than —CH₂ and was removed before —CH₂ in the range of 3 600~2 800 cm^-1. The number of auto-peaks was 6, 5, 6 respectively in the two-dimensional perturbation correlation infrared spectroscopy of chicken, dairy and pig manure biochar. The changing intensity of each auto-peak was (chicken manure biochar) aromatic C=C> C=O >Si—O/C—O>P—O/C—H; (dairy manure biochar) C=O > C=C and P—O/C—H>C—OH, C—O/Si—O; (pig manure biochar) C=O > C=C >COO^->Carboxylic C—OH> P—O/C—H=C—O /Si—O. The groups of C=O and C=C broke and reconstituted, and C=O broke ahead of C=C. However, there were differences in the functional groups of different animal manure biochars, mainly the change of C—O/Si—O was prior to P—O/C—H in chicken manure biochar, while P—O/C—H in dairy manure biochar changed earlier than C—O/Si—O, and C—O/Si—O and P—O/C—H in pig manure biochar occurred simultaneously in the range of 1 800~800 cm^-1.