Beta-oxidation(β-oxidation) is an important metabolic process involving multiple steps by which fatty acid molecules are broken down to produce energy. The very long-chain fatty acids (VLCFAs), a type of fatty acid (FA), are usually highly toxic when free in vivo, and their oxidative metabolism depends on the peroxisomal β-oxidation. For a long time, although β-oxidation takes place in both mitochondria and peroxisomes, most studies have been keen to explore the mechanism of β-oxidation in mitochondria while ignoring the importance of peroxisomal β-oxidation. However, current studies indicate that it is hard to provide effective treatment for diseases caused by the disorder of peroxisomal β-oxidation, such as X-ALD, SCOX deficiency, and D-BP deficiency; thus, actions should be taken to solve this problem. Based on existing research results, this review will summarize the importance of peroxisomal β-oxidation and help further learning.