Haematococcus pluvialis, a natural source of astaxanthin, has garnered significant attention in the pharmaceutical, food, and feed industries. However, challenges such as slow growth rates, low astaxanthin yields, and high production costs have hindered its industrialization. Chemical inducers have attracted extensive attention because they can promote the synthesis of astaxanthin in microalgae more efficiently by directly or indirectly acting on the metabolic pathways in cells. This review summarizes recent research progress on the regulatory effect of chemical inducers on astaxanthin accumulation in H. pluvialis. It focuses on the mechanisms by which metabolites of the tricarboxylic acid (TCA) cycle, phytohormones, signaling molecules, and other chemical substances enhance astaxanthin synthesis and stress resistance in this microalga. This review aims to provide theoretical support and practical guidance for achieving targeted regulation of metabolite accumulation in H. pluvialis.