Carotenoids are secondary metabolites and pigments widely existed in horticultural plants.They play an important role in the growth and development of plants and ornamental value.It is also a natural active substance with high-value， which is beneficial to human health.Therefore， the metabolic regulation of carotenoids has always been a research hotspot in horticultural plants.The differences in the components and contents of carotenoid are one of the important reasons for the diversity of color and nutritional value of horticultural plants.Analyzing the molecular mechanism of the formation of high-quality traits is the premise and basis for directional improvement.To date， the metabolic pathway of plant carotenoids has been clarified.A large number of studies have shown that mutations of promoters and coding regions in metabolic pathways are the key factors causing the diversity of carotenoid metabolism.This article reviewed the strategies of studying the genetic mechanism of carotenoid variation in horticultural plants， the types of variation in promoters and coding regions， and the effects of variation on carotenoid metabolism.It will provide a theoretical basis for the directional improvement of carotenoids in horticultural plants.