Corn steep liquer, a byproduct of corn starch production, is highly productive and nutritious, containing a large quantity of amino acids, B vitamins and growth-promoting factors, which plays an important role in fermentation engineering, feed additives and pharmaceuticals. Due to sulfite residue, mycotoxin contamination and other issues, its application in various fields is seriously limited, resulting in resource waste, environmental pollution and economic loss. This paper reviews the techniques for removing antinutritional factors, phytic acid, and sulfites in corn syrup and the pollution, prevention of fungal toxins as well as the most recent application of it in single-cell protein, amino acid fermentation and biofertilizer, aiming to provide ideas for the comprehensive utilization of corn steep liquer and maximize its economic benefits.