The invention relates to a method for breaking walls of Haematococcus pluvialis and extracting astaxanthin. The method comprises the following steps: (S1) uniformly mixing Haematococcus pluvialis powder with a concentrated sulfuric acid-alcohol system, stirring at 30-70 DEG C, and carrying out wall breaking for a preset time, so as to obtain an alcohol solution containing wall-broken Haematococcus pluvialis; and (S2) adding an extraction solvent into the alcohol solution containing the wall-broken Haematococcus pluvialis obtained in the step (S1), carrying out stirring extraction at 30-70 DEG C, layering, and concentrating supernate, so as to obtain an extract containing the astaxanthin. The method has the beneficial effects that the wall-breaking temperature and the extraction temperature are relatively low, reaction conditions are mild, the loss of astaxanthin is reduced, and the content of the astaxanthin in a crude extract can reach up to about 10%, so that the subsequent purification level of difficulty can be lowered, and the commercialization of the astaxanthin is promoted. Compared with existing methods, the method has the advantages that the operation steps are relatively simplified and the type and use amount of reagents are less, so that the energy consumption can be reduced, and the comprehensive cost can be lowered.