NOVELTY - A core-shell type molecular sieve microsphere comprises A-type molecular sieve as shell and A and X-type molecular sieve as core in which X-type molecular sieve amount in core is 50-90 mass%, core-shell type molecular sieve microsphere has 0.5-3 mm diameter and 1-12 mu m shell layer thickness, and core-shell type molecular sieve microsphere is sodium (Na) ion-type, calcium (Ca) ion-type, or potassium (K) ion-type.    USE - Core-shell type molecular sieve microsphere for gas adsorption and separation of carbon dioxide, methane, and nitrogen (claimed).    ADVANTAGE - The microsphere high adsorption capacity, selectivity, mechanical strength, thermal stability, and anti-corrosion property, short production time, low cost, and repeatable use.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of core-shell type molecular sieve microsphere which involves mixing chitosan, acetic acid (HAc) and silica sol to obtain silicon solution in which molar ratio chitosan:HAc:silicon dioxide (SiO2):water (H2O) is 0.0003-0.0009:0.3-0.5:1.35-2.7:50-100, mixing sodium hydroxide (NaOH), sodium aluminate (NaAlO2), and H2O to obtain aluminum solution in which molar ratio sodium oxide (Na2O):aluminum oxide (Al2O3):H2O is 2-6:1-3:30-60, dropwise adding silicon solution to aluminum solution to form small spherical particle, dipping, hydrothermal reacting to obtain spherical particle, water washing, drying to obtain polysaccharide/NaA/NaX composite material sell, calcining to remove chitosan and obtain NaA-NaX molecular sieve microsphere bonding agent, mixing NaAlO2, sodium silicate (Na2O3Si), and H2O to obtain long film solution in which molar ratio NaAlO2:Na2O3Si:H2O is 0.5-2:0.3-1.2:60-200, aging long film solution, adding NaA-NaX molecular sieve microsphere, aging, heating to synthesize solution, washing product with water until neutral, drying to obtain NaA shell and NaA and NaX as Na ion core-shell type molecular sieve microsphere core, or adding K ions or Ca ions to Na ion-core-shell type molecular sieve microsphere, ion exchanging, water washing, and drying to obtain K ion type or Ca-ion type microsphere.    DESCRIPTION OF DRAWING(S) - The drawing shows an X-ray diffraction pattern of core-shell type molecular sieve microsphere sample.