Idiopathic semen quality abnormalities include idiopathic oligozoospermia, asthenospermia, teratospermia, azoospermia and idiopathic abnormal semen liquefaction. The possible causes of idiopathic semen quality abnormality include age, non-inflammatory function changes of subsidiary gonadal organs, infection, genetic abnormalities, sperm mitochondrial changes, effects of environmental pollutants, and subtle hormonal changes. The diagnosis of idiopathic oligozoospermia, asthenospermia, teratospermia and azoospermia require detailed inquiry of the case history, physical examination, semen analysis, determination of reproductive hormones, genetic and immunological examinations, and so on, to exclude possible known causes. The treatment of idiopathic oligozoospermia, asthenospermia, and teratospermia may involve the use of Western medicines, such as clomiphene citrate, tamoxifen, recombinant FSH, Andriol, compound zinc and selenium, L-carnitine, recombinant growth hormone and pentoxifylline, the application of traditional Chinese drugs, or the combination of traditional Chinese and Western medicine. Idiopathic azoospermia can be treated by assisted reproductive technology based on the medication of spermatogenesis-promoting drugs, and idiopathic abnormal semen liquefaction can be managed with traditional Chinese drugs, integrated traditional Chinese and Western medicine, or in vitro semen processing technology. With the development of diagnostic technology, it is expected that more specific therapeutic methods will be established for idiopathic semen quality abnormalities and their incidence will be reduced.