Genome-wide association studies (GWAS) have identified thousands of genetic loci associated with complex diseases or traits. However, the exact biological functions of these loci are largely unknown. Recent functional annotation indicates that the majority of disease/trait associated loci are concentrated in regulatory DNA of human genome. Expression quantitative trait loci (eQTL) analyses, chromosome conformation capture related methods and genome editing methods (such as CRISPR/Cas9) may facilitate the functional study of these loci. Research on noncoding RNAs and rare variants may improve the functional understanding. These efforts may promise translation of GWAS findings to clinical practices.