The invention discloses a three-frequency absorber based on an optical Tamm state. The three-frequency absorber is characterized in that the three-frequency absorber comprises a metal layer M1, a defect layer D1, a DBR1 layer, a DBR2 layer, a defect layer D2 and a metal layer M2 which are successively arranged; the D1 and the D2 are titanium dioxide layers; the DBR1 layer is obtained through periodically and alternately arranging two semiconductor materials (A and B), namely silicon dioxide and titanium dioxide; and the DBR2 layer is obtained through periodically and alternately arranging twosemiconductor materials (B and A), namely the silicon dioxide and the silicon dioxide. According to the three-frequency absorber, a coupling function among multiple optical Tamm states is utilized forrealizing three-frequency absorption; the D1 and the D2 are designed for changing an absorption wavelength; and an incident light angle is changed for flexibly adjusting absorption wavelength. Compared with an absorber which is manufactured according to a standard etching method, the absorber according to the invention is realized according to a metal-organic chemical vapor deposition method andhas advantages of simple structure, and high convenience in preparation.