Anthocyanins and betalains are both natural water-soluble pigments with similar distribution and functions in plants. Anthocyanins is a type of phenylalanine-derived pigment， and the betalains is a tyrosine-derived pigment that contains the chromophore betalamic acid. Anthocyanins are widely distributed in plants， but in Caryophyllaceae plants， betalains present instead of anthocyanins. It is worth attention that anthocyanins and betalains have never been found in the same plant at the same time. This mutual exclusion may be raised by accident in evolution， or the co-existence of both pigments would bring troubles in plant survival. This article reviewed and discussed the general characters of anthocyanins and betalains， the biosynthetic pathways and their regulations， the cases of induced co-existence of the two pigments， and the possible reasons for the mutual exclusion between the two pigments. In addition， the possible mechanism of the mutual repulsion of the two pigments， the research focuses for the future， and the possible application value in molecular breeding are also prospected. The purpose of this article is to better understand the relationship between anthocyanins and betalains through the review and prospect of previous studies， reveal the mechanisms for their mutual exclusion， as well as provide new ideas and methods for research and application in related fields.