NOVELTY - Preparation of biomass soil comprises taking bamboo, wood, and charcoal, mixing, and combusting; weighing e.g. honeysuckle, sage, and Angelica, mixing, drying, and grinding; weighing straw and biogas, mixing with chopped straw residue, stacking, and fermenting; weighing soybean residue and corn residue, mixing, adding into sealed cylinder, adding water, sealing, and removing grain residue; and weighing e.g. humus, sand, compost soil, perlite, vermiculite, fulvic acid, mosquito-repellent powder, and nitrogen-fixing bacteria powder, mixing, stirring, sealing in plastic bag, and storing.    USE - Method for preparing biomass soil used for cultivating flowers (claimed).    ADVANTAGE - The biomass soil has low cost, simple preparation process, mosquito-repellent effect, good soil fertility, moisturizing effect, and slow release fertilizer effect, prevents frequent watering, and contains needed nutritional elements.    DETAILED DESCRIPTION - Preparation of biomass soil comprises: (A) taking 30 wt.% bamboo, 35 wt.% wood, and 35 wt.% charcoal, mixing, and combusting; (B) weighing 2.5 pts. wt. honeysuckle, 5 pts. wt. sage, 5 pts. wt. Angelica, 2 pts. wt. clove, 4 pts. wt. mint leaves, 4 pts. wt. folium artemisiae argyi, 5 pts. wt. rhizoma acori graminei, and 1.5 pts. wt. Agastache rugosus, mixing, drying, and grinding; weighing 10 pts. wt. straw and 8 pts. wt. biogas, mixing with chopped straw residue, stacking, and fermenting for 30-40 days; (C) weighing 5 pts. wt. soybean residue and 5 pts. wt. corn residue, mixing, adding into sealed cylinder, adding 50 pts. wt. water, sealing for 30 days, and removing grain residue; and (D) weighing 36 pts. wt. humus, 8 pts. wt. sand, 8 pts. wt. compost soil, 5 pts. wt. perlite, 4 pts. wt. vermiculite, 5 pts. wt. fulvic acid, 8 pts. wt. wood ash, 9 pts. wt. mosquito-repellent powder, 8 pts. wt. nitrogen-fixing bacteria powder, 55 pts. wt. marsh rot straw manure, 35 pts. wt. fertilizer residue cereals, 15 pts. wt. diatomite, and 25 pts. wt. fine silica powder, mixing, stirring, sealing in plastic bag, and storing for more than a week.