Objective To explore the change of Wnt inhibitor factor-1 (Wif-1) expression in the spinal cord of the adult amyotrophic lateral sclerosis (ALS) transgenic mice，in order to investigate the function of Wif-1 in the pathogenesis of ALS. Methods Some ALS transgenic mice and wild type mice were anesthetized deeply and then perfused intracardially with 4% paraformaldehyde at 95 days, 108 days and 122 days. The spinal cords were separated and sectioned. The distribution and change of Wif-1 in the spinal cords were detected by immunofluorescence labeling technology. Some animals were killed and the spinal cords were separated at 95days, 108 days and 122 days. The expression of Wif-1mRNA and Wif-1 protein in the spinal cords were detected using reverse transcription polymerase chain reaction (RT-PCR) and Western blotting techniques. Results Wif-1 positive cells were detected in the central canal, gray matter and white matter of the adult spinal cord in ALS transgenic mice and wild type mice. Within the gray matter, most of the positive cells were located in the ventral horn. In the white matter, the positive reaction was detected in the neuron axon. Compared with the wild type mice, the Wif-1 positive cells were increased significantly in the ALS transgenic mice, the expression of Wif-1 mRNA and Wif-1 protein were increased at 108 days and 122 days, there were significant differences ( EM>P/EM> 0. 05), especially at 108 days. At 95 days, there was no significant difference. Conclusion Wif-1 positive cells and Wif-1 mRNA and protein expression were all significantly increased in the pathogenesis of ALS transgenic mice. The expression of Wif-1 was closely rel