The invention discloses a composite absorbing layer pyroelectric infrared detector, and belongs to the technical field of pyroelectric detectors. According to the pyroelectric infrared detector, an absorbing layer comprises a titanium metal layer (1), a dielectric layer (2), a nichrome alloy layer (3), a lithium tantalate crystal layer (4) and a reflecting layer (5) which are arranged from the top layer to the bottom layer in turn. The nichrome alloy layer (3) is deposited on the top surface of the lithium tantalate crystal layer (4). The reflecting layer (5) is deposited on the bottom surface of the lithium tantalate crystal layer (4). The titanium metal layer (1) is deposited on the top surface of the dielectric layer (2). Compared with a single metal absorbing layer film acting as a heat sensitive layer, the prepared composite absorbing layer of the pyroelectric infrared detector has better surface compactness, high absorption coefficient and low heat loss and can acquire high performance heat response so as to be favorable for preparation of the high-precision pyroelectric infrared detector.