To investigate the cytogenetic characteristics of multiple myeloma and its relationship with clinical prognosis, 68 cases were collected and chromosome specimens of bone marrow cells were prepared by 24-hour culture, and G-banding technique was used for karyotype analysis. The results showed that the detected chromosome aberration rate was 19.1% (13/68). The abnormal clones existed mosaically with normal clones. Numerous aberrations were manifested by aneuploidy, mainly by hyperdiploidy or hypodiploidy. Structural aberrations involved t (11; 14), chromosome 1 and various kinds of marker chromosomes. Cases which had very complex aberrations revealed poor prognosis. It is concluded that chromosome complex aberration is the mainly cytogenetic characteristics of multiple myeloma, and multiple numerous and structural aberrations are involved. Cytogenetic detection should be performed both at diagnosis and at disease progression so as to evaluate prognosis.