Bitter compounds widely exist in foods and have an important impact on food flavor. The major bitter compounds in foods include amino acids, peptides, polyphenols, alkaloids, and inorganic salts. Bitterness is perceived through binding between bitter compounds and the specific sites of the 25 human bitter taste receptors (hTAS2Rs), which further activates the downstream signal pathway mediated by G protein, converting chemical signals into electrical signals and transmitting them to the brain. Some foods with strong bitterness taste are not well accepted by consumers, so appropriately reducing bitterness in foods can improve consumers’ preference. At present, there are two main methods to reduce the perception of food bitterness: 1) masking bitterness by polymerization/complexation or flavor interaction, and 2) removing bitterness by reducing the content of bitter compounds or changing their structure. In this paper, the bitter compounds in foods, the analytical methods for them, the mechanism of bitterness perception and the methods used to reduce bitterness perception are reviewed in an effort to provide theoretical guidance for food bitterness regulation.