The invention relates to a salbutamol sulfate film-controlled sustained-release pellet capsule. The sustained-release film of the pellet adopts Kollicoat SR30D as a film-forming material, and the pellet core contains high-expandability sodium carboxymethyl starch, and pharmaceutically acceptable The commonly used excipients of the sustained-release pellets, the excipient is preferably microcrystalline cellulose, wherein, the sodium carboxymethyl starch in the pellet core accounts for 5-20% of the weight of the pellet core. The sustained-release coating film comprises Kollicoat SR30D, plasticizer triethyl citrate and anti-sticking agent talcum powder, and its ratio is preferably Kollicoat SR 30D: triethyl citrate: talcum powder=30:1:4, coating weight gain Preferably it is 19 to 38%. Because the ball core contains sodium carboxymethyl starch, which has high water swelling property, it will swell obviously after absorbing water, resulting in the expansion of the slow-release coating film, the thickness becomes thinner, the pore size of the water-permeable micropores becomes larger, and the permeability becomes better. , which compensates for the decrease in permeability caused by membrane aging, so that the release rate in the middle and late stages is basically constant, and the residue in the end stage is small, which can always maintain a stable release performance within the validity period.