The present invention provides a method and a system for preparing pulp for paper with grass straws as raw material. The method of the present invention includes the following steps: 1) adding water in raw material for pulping, performing a first enzymolysis with ligninolytic enzyme; 2) cooking the first enzymolysis product at 80-130° C.; 3) performing second enzymolysis with hemicellulase to the cooked product. The method of the present invention is able to improve the pulp yield, reduce discharge of pollutants from black liquor, lower alkali consumption and energy consumption, and facilitate extraction of lignin and C-5 sugars, and pulp has a high quality.
