Disclosed are methods for the pre-treatment of lignocellulose by adding an alkali or acid reagent(s) during the densification thereof, and for the biotransformation thereof. In the method, an alkali reagent(s) or acid reagent(s) is added to a lignocellulosic raw material for a densification pre-treatment to form an alkali- or acid-containing densified lignocellulose with a compressed compact shape, thereby achieving the pre-treatment. The acid or alkali in the pre-treated lignocellulose can further pre-treat the lignocellulosic raw material in a mild manner during the subsequent transportation and storage processes. If a subsequent pre-treatment is needed, then the severity thereof is reduced substantially; in addition, the uniform mixing of the acid or alkali with the lignocellulose and a large density of the raw material promote a high efficiency and a high loading capacity of the subsequent pre-treatment of the densified lignocellulose. The method is simple and efficient. The resulting lignocellulosic raw material has a large density, will not easily degrade or rot due to the inclusion of an acid or alkali, which is conducive to transportation and storage, and a high equipment utilization rate during the subsequent treatment is achieved.