The invention provides a selective hydrogenation method of alkyne in a C4 hydrocarbon stream. The selective hydrogenation method comprises the steps of introducing the C4 hydrocarbon stream containing alkyne together with hydrogen into a hydrocarbon reactor with a supported palladium catalyst, carrying out selective hydrocarbon on alkyne in the C4 hydrocarbon stream at the inlet temperature of 10-80 DEG C in a molar ratio of hydrogen to alkyne of 1-10 at the reaction pressure of 0.1-4MPa so as to form olefin/alkadiene, then removing alkyne, wherein the supported palladium catalyst comprises a carrier, palladium and a selectable modified component. In the invention, a carbon monoxide absorption in situ infrared spectroscopy is used so as to test olefin/alkadiene at the temperature of 40 DEG C, and in the obtained infrared spectrogram, the area ratio of bridge type absorption peak at the part of 1930-1990cm<-1> to bridge type absorption peak at the part of 1870-1930cm<-1> is less than 0.2, more preferably 0.15. The method has high selectivity on the selective hydrogenation of alkyne in the C4 hydrocarbon stream and can operate for a long period.