NOVELTY - Forming mushroom cultivation matrix involves: cutting crop straw into sections and crushing, then adding water (5-30 wt.%) for soaking the straw into cylinder for compressing rice bar particle with diameter of 0.6-0.8 cm and length of 0.8-1.0 cm to obtain compressed straw; mixing coarse sawdust (25-35%), fine sawdust (15-25%), permeated compressed straw particle (25-35%), bran (10-15%) and gypsum (1.0-1.5%) at a natural pH, and adding water; and pouring the processed mixed cultivation material into an edible fungus culture bag for sterilization processing.    USE - For the preparation of mushroom cultivation matrix which is useful for cultivating mushroom (claimed).    ADVANTAGE - The present method utilizes compressed crop straw that replaces wood as raw material for planting mushroom, which not only solves the problem of mushroom growing raw material wood chip to supply falls short of demand, but also effectively protects the forest resource, reduces environmental pollution, and saves the cost. Also the compressed crop straw particle is provided with wide raw material source, easy production, storage and transportation guaranteeing the stability of mushroom cultivation matrix nutrient. The present culture medium provides nutrition, has more balanced design, is good for mushroom growth, reduces the raw material cost and achieves culturing of mushroom at reduced culturing time of 5-10% and increased yield, while maintaining the quality of mushroom.    DETAILED DESCRIPTION - Preparation of mushroom cultivation matrix with compressed straw, involves: cutting the crop straw into sections and crushing, then adding water (5-30 wt.%) for soaking the straw into cylinder for compressing rice bar particle with diameter of 0.6-0.8 cm and length of 0.8-1.0 cm to obtain compressed straw; mixing the compressed straw particle and water at a wt. ratio of 1:1-1.5, covering for 20-30 minutes, and permeating the compressed straw particle with water; mixing coarse sawdust (25-35%), fine sawdust (15-25%), permeated compressed straw particle (25-35%), bran (10-15%) and gypsum (1.0-1.5%) at a natural pH, and adding water (1.2-1.5 times of total volume); and pouring the processed mixed cultivation material into an edible fungus culture bag for sterilization processing, using high pressure steam sterilization for 3-4 hours or using normal temperature and pressure steam sterilization for 12-16 hours, then obtaining cultivation matrix for cultivating mushroom.