TECHNOLOGY FOCUS - AGRICULTURE - Preferred Component: Biomass is corn straw, bagasse, rice hull, saw dust, wood, cellulose, or hemicellulose.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: Carbohydrate is starch, sucrose, glucose, inulin, fructose, xylose, and catalyst is Lewis acid catalyst and solid acid catalyst. Inorganic salt is halide and sulfate. Solid acid catalyst is Lewis acid and Bronsted acid in which Lewis acid is for isomerization and Bronsted acid is for hydrolysis and dehydration, catalyst is oxide of transition metal, phosphate, sulfate, and molecular sieve and clay mineral obtained by transition metal ion exchange. Transition metal oxide, phosphate, and sulfate is derived from co-precipitation, sol-gel method, and hydro-thermal synthesis, molecular sieve and clay mineral as transition metal ion exchange is transition metal chloride, nitrate, acetate, bromide, molecular sieve or mineral is zeolite socony mobil (ZSM)-5, mobil crystalline material (MCM)-41, mesoporous silica (SBA)-15, 5A, 13X, calcium (Ca)-montmorillonite, or sodium (Na)-montmorillonite, and transition metal contains titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), tin (Sn), zinc (Zn), iron (Fe), and/or cobalt (Co).    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: Organic solvent is tetrahydrofuran, toluene, hexane, acetone, methyl isobutyl ketone, 1,4-dioxane, 1-butanol, and 2-butanol. Preferred Process: Preparation of furfural compound from biomass involves performing reaction continuously in fixed bed reactor, separating carbohydrate-containing saturated inorganic salt aqueous solution and organic solvent, controlling temperature at 100-200 degrees C, and controlling space velocity at 5-20 h-1. Preparation of furfural compound from biomass involves standing, forming furfural in which 5-hydroxymethyl furfural in organic phase sets at upper layer and solid acid catalyst, inorganic salt, and unreacted substrate remained in bottom of water phase, separating to obtain furfural and 5-hydroxymethyl furfural organic solution, decompressing and distilling organic phase, drying, and preparing.