NOVELTY - Preparation of improved strong saline soil comprises selecting cow dung and cotton field residue containing cotton stalk and cotton shell; drying cow dung, sieving; drying cotton stalk and cotton shell, hot cracking, heating, collecting solid carbon stalk and wood vinegar raw liquid, filtering, crushing, and sieving; mixing cow dung and carbon stalk, drying, uniformly mixing, stirring, sprinkling to the mixture, mixing, placing into sealed environment, anaerobically fermenting to obtain cotton stalk carbon fertilizer; and mixing wood vinegar liquid, cotton stalk carbon fertilizer and water.    USE - Method for preparing improved strong saline soil (claimed).    ADVANTAGE - The method has low cost, increases utilization rate, and improves saline soil.    DETAILED DESCRIPTION - Preparation of improved strong saline soil comprises selecting cow dung and cotton field residue containing cotton stalk and cotton shell; drying cow dung until moisture content of less than 20%, sieving through 2 mm sieve; drying cotton stalk and cotton shell until moisture content of less than 13%, hot cracking to 0-500 degrees C where cracking unit is divided into 6 sections every 30-60 minutes: o-50 degrees C on first section, more than 50-120 degrees C on second section, more than 120-150 degrees C on third section, 150-270 degrees C on fourth section, more than 270-450 degrees C on fifth section and more than 450-500 degrees C on sixth section; heating to 500 degrees C, collecting solid carbon stalk and wood vinegar raw liquid, filtering, crushing, and sieving through 2 mm sieve; mixing cow dung and carbon stalk at weight ratio of 1:2-4, drying, uniformly mixing, stirring, sprinkling to the mixture until water content of 60-70%, mixing, placing into sealed environment, and anaerobically fermenting at 20-25 degrees C for 2-6 weeks to obtain cotton stalk carbon fertilizer; and mixing wood vinegar liquid, cotton stalk carbon fertilizer and water at weight ratio of 0.03-0.04:10-22:40-60.