The invention belongs to the field of bioinstrumentation and relates to a multi-test-line immunochromatographic test strip for semi-quantitatively detecting aflatoxin B1, comprising a paperboard, wherein a water absorbent pad, a detection pad, a gold-labeled pad and a sample pad are adhered on one surface of the paperboard from top to bottom in sequence, wherein adjacent pads are overlapped and connected at the connection part, the detection pad takes a nitrocellulose film as a base pad, the nitrocellulose film is provided with a transverse quality control line, a detection line I, a detection line II and a detection line III from top to bottom, wherein the quality control line is wrapped with a rabbit anti-mouse polyclonal antibody, and the detection line I, the detection line II and the detection line III are respectively wrapped with an aflatoxin B1-bovine serum albumin (AFB1-BSA) conjugate; and the gold-labeled pad is transversely sprayed with a nanogold-labeled aflatoxin B1 monoclonal antibody. The immunochromatographic test strip is used for semi-quantitatively detecting the aflatoxin B1 and has the characteristics of fast detection, simple operation and high sensitivity.