Discloses are a method for preparing fluff pulp from bamboos, and the fluff pulp prepared thereby. The method comprises the following steps: treating the bamboos with high-concentration alkali at a relatively mild temperature, after a certain period of treatment, replacing a treatment liquid for separating hemicellulose with a weak black liquor; Kraft cooking the treated bamboos to obtain unbleached bamboo pulp, removing rejects in the unbleached bamboo pulp by using a slotted screen; then removing miscellaneous cells by using a microporous sieve; carrying out two stages of oxygen delignification on the screened pulp; carrying out ECF bleaching treatment of a D0EpD1P process; and finally obtaining the bamboo fluff pulp which has high whiteness, low DCM extract content, low ash content and long fiber length, contains 4.2-4.6 million fibers per gram, and has relatively high bulkiness.