TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Catalyst: The hydrogenating catalyst is palladium, ruthenium, platinum, nickel arsenide on a carrier, comprising titanium dioxide, silicon dioxide, aluminum oxide, zinc oxide, tin oxide, and/or molecular sieve. It also contains an auxiliary catalyst comprising potassium, sodium, lithium, calcium, magnesium, barium, copper, silver, gold, zinc, lanthanum, cerium, molybdenum, tungsten, antimony, arsenic, bismuth, and/or vanadium.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: Selective hydrogenation of unsaturated hydrocarbons comprises:(A) cooling raw materials containing olefin to 10-100 degrees C through heat exchanger, sending materials in mixed phase hydrogenating reactor, and selectively hydrogenating portion of the hydrocarbon;(B) cooling effluent from hydrogenating reactor though a cooler, and sending to front-end depropanizer separating gaseous material stream containing 3C hydrocarbon and lighter component and liquid material stream containing 4C hydrocarbon and heavier component;(C) sending the gaseous material stream to gaseous hydrogenating reactor, selectively hydrogenating contained acetylene, while sending the liquid material stream to a depentanizer separating into material stream containing 4-5C hydrocarbon and material stream containing 6C hydrocarbon and heavier component;(D) circulating portion of material stream containing 6C hydrocarbon and heavier component to the mixed phase hydrogenating reactor, and collecting residual portion;(E) cooling and partially condensing gaseous material stream from the gaseous hydrogenating reactor, and circulating the condensed stream to top of front-end depropanizer as reflux liquor; and(F) sending the uncondensed gaseous material stream to downstream separation region containing demethanizer and/or deethanizer.Preferred Material: The raw material comprises hydrogen, methane, carbon monoxide, acetylene, ethylene, ethane, propylene, propane, butylenes, butyne, 1,3-butadiene, butane, 5-8C non-aromatic hydrocarbon, benzene, toluene, or styrene. Preferred Condition: The mixed phase hydrogenating reaction is operated at 10-100 degrees C and 0.7-4 MPa pressure in presence of hydrogenating catalyst containing group VIII metal or subgroup I metal. The gaseous hydrogenating reactor is operated at 30-200 degrees C under 0.6-4 MPa in presence of hydrogenating catalyst containing group VIII metal.