The invention provides a method for promoting synthesis of
microcystis astaxanthin by adjusting the concentration of a stress substance, which comprises the following steps of: firstly, culturing
microcystis algal bloom or
microcystis aeruginosa to a logarithmic phase by adopting a BG11 culture medium under the conditions of specific temperature, illumination and shaking table rotating speed, and adjusting the
cell density by centrifuging and resuspending; then, NaCl, KCl, beta-violet
ketone,
longifolene and H2O2 with different concentrations are added into the
algae liquid respectively, control is set, through multi-dimensional index measurement, the
algae cell density, the ROS level, the
photosynthetic pigment content, the photosynthetic performance and the level of
astaxanthin and a precursor thereof are monitored when treatment is carried out for 0 day, 2 days, 4 days and 6 days, the expression quantity of
astaxanthin biosynthesis related genes is further analyzed, and the astaxanthin
biosynthesis related genes are obtained. Therefore, the optimal concentration of NaCl, KCl, beta-violet
ketone,
longifolene and H2O2 is determined, the effect of promoting
astaxanthin synthesis is compared, and a theoretical basis and a precise regulation and control method are provided for industrial production of astaxanthin by using microcystis.