Multiple morphological abnormalities of sperm flagella (MMAF) is a type of teratospermia caused by genetic defects. The sperm motility is low due to absence of flagella, shortness, curling, bending or irregularity of sperms, and combination of various abnormalities. Ultrastructure may show flagellum assembly abnormalities, which are mainly manifested by the absence of microtubules in the axoneme and defects of various structures such as fibrous sheath, outer dense fiber, mitochondrial sheath and dynein arms. MMAF males are unable to reproduce naturally and require assisted reproductive technology to obtain offsprings. For the heterogeneity of molecular etiology of MMAF, the outcome of assisted reproduction may be different. Here the candidate genes of MMAF and their functional mechanisms are summarized, which may provide a reference for clinical diagnosis, treatment and research for this disorder.