Haematococcus pluvialis, as the most potential natural source of astaxanthin, which is a powerful antioxidant with high economic value, has attracted more and more scientific attention in recent years. An in-depth understanding of the mechanism for how H. pluvialis produces astaxanthin requires the intensive investigations on its genetic information. In particular, many reported studies were based on a variety of RNA analyses. However, it is difficult to extract RNA with high quality and quantity from H. pluvialis, because of the blockage from its thick cell wall and contamination by a large quantity of pigments, polysaccharides, and lipids. Therefore, we proposed an optimized Trizol-based RNA extraction method for H. pluvialis by investigating the effect of cell wall broken ways, algal strains, and cell growth status on total RNA isolation. Using this rapid, convenient, and cost-saving method, isolated H. pluvialis RNA had high quantity and quality (with an RNA integrity number of 7.0 and a concentration of 1604.1 ng/μL) equivalent to that isolated by commercial kit, enabling its applications into downstream RNA analyses.