The genera of Lolium and Festuca include many cool season forage grasses and turf species, such as Italian ryegrass (L. multiflorum), perennial ryegrass (L. perenne), tall fescue (F. arundinacea) and meadow fescue (F. pratensis). The ryegrass can be used as hay and silage, due to its high yield, broad adaptability, rich nutrition, good palatability, and high digestibility; and it was considered as a high-quality feed. But because its cultivation region in China is limited by geography factors, the current proportion of ryegrass in China’s grass pasture industry is still very small. In order to increase the proportion of ryegrass cultivation, the use of molecular breeding methods to breed excellent varieties maybe one of the key directions. In this review, we summarized recent progress in the Lolium-Festuca complex, especially in Lolium, including classification and evolution study, molecular marker development, linkage map construction, quantitative trait locus (QTL) and genome wide association study (GWAS) for important agronomic traits, genome sequences, transcriptome analysis, gene cloning and variety breeding. We also brought up some biological issues in Lolium species that need to be resolved, and try to provide some reference for further strengthening the basic biological research and molecular breeding of ryegrass.