Abstract: Occupational cadmium intoxication targets kidney but also possibly involves nervous system. A patient showing mental disturbance had been diagnosed as occupational cadmium intoxication by the only evidence of long-term cadmium exposure. However, the possibility of occupational cadmium intoxication was excluded by normal urine cadmium concentration and lack of renal injury. The patient was eventually proved to be infected with neurosyphilis after other extensive tests. This case report reminds that we should collect all-around medical history, expand diagnostic thoughts and avoid compulsory logic so as to prevent misdiagnosis or mistreatment.