A preparing method of fecula-fatty acid modified micro particle papermaking stuffing, including: firstly blending, boiling and stirring the fecula-fatty acid modified particle solution and micro particle stuffing to execute reaction; adding cross linking agent reaction liquid; adding fatty acid reaction liquid, regulating PH value of the mixture into 11; adding acidic solution into the mixture for neutralizing, regulating PH value to 5, thereby the compositions deposit out; collecting outcome yield and washing with water, drying, cooling and comminuting into granule with graininess not more than 80 mesh, thereby obtaining micro particles stuffing fecula-fatty acid complexes. The invention can substitute 5-35% of plant fibre as stuffing to apply in paper manufacturing industry, and can remarkably improve strength character and optical characteristic of the paper sheet.