The usages of microalgae to produce a diverse array of chemical compounds including polysaccharides, lipids, proteins, carotenoids, pigments, vitamins, steroids, pharmaceuticals, and other fine chemicals, as well as hydrogen and hydrocarbons. One among the microalgae group is Haematococcus are the most promising genera for the production of natural bioactive compounds including astaxanthin, carotenoids, zeaxanthin, lutein and canthaxanthin compounds that are highly associated with cancer prevention, immune stimulation, and a reduction in free radicals. The Haematococcus microalgal compounds, viz. astaxanthin, carotenoids, zeaxanthin, lutein, and canthaxanthin possess antioxidant properties. A mechanism by which the unicellular green alga Haematococcus displays exceptional stress resistance has recently attracted considerable interest through its ability to produce large quantities of the astaxanthin, carotenoids, zeaxanthin, lutein, canthaxanthin, and tocopherol. There is evidence that secondary compounds accumulation in Haematococcus are induced by a variety of environmental factors and most of the compounds produced are esterified and deposited in stresses that limit cell growth when exposed to light. The presence of lipid globules outside the chloroplast further supports this assumption, as well as a remarkable morphological and biochemical pattern. The bioactive compounds are thought to be the “transformation” from green motile cells into inert red products of a defense mechanism, as opposed to the defense mechanisms themselves. Despite the fact that this transformation substance was only discovered a few years ago, we cannot exclude the possibility that other protective mechanisms may have existed at the time. Comprehending the biosynthetic pathway and the pigment accumulation is critical to understanding the transformation process. The synthetic form of bioactive compounds currently dominates the market because it exhibits a wide range of biological activities and a high economic potential. In addition, due to its low biomass and bioactive compounds productivity, bioactive compounds extracted from this microalga are still expensive due to its difficult bioprocess. In this chapter, we focused on optimization of physical and chemical parameters for the cultivation of microalga Haematococcus sp. and also incorporate with new technological approaches for large scale production, harvesting, and higher biomass production. © 2024 Elsevier B.V., All rights reserved.