The present invention discloses a Rhizoma Corydalis Decumbentis total alkaloids extract, its preparation method, pharmaceutical composition containing same. The total alkaloids mainly comprise : macleyine, tetrahydropalmatine, bicucalline, palmatine hydrochloride, 'xiawuning' alkaloid, corydaline harmine, other alkaloid and extract. The preparation method is : using Rhizoma Corydalis Decumbentis as material, adding right amount of polar solvent for leaching, merging the leachate, carrying out large pore adsorption resin chromatography, eluting impurity with diluted acid and alkaline aqueous solution orderly, eluting using polar organic solvent, collecting elution liquor, eliminating impurity further by alumina column adsorption, Collecting after-column liquid, concentrating liquor to obtain the Rhizoma Corydalis Decumbentis total alkaloids extract. The present invention also discloses a pharmaceutical composition containing the total alkaloids extract and uses of the pharmaceutical composition in preparing tablet, capsule, soft capsule, suppository, granula, transdermal absorption agent, drop pills, oral disintegrating agent, slow release agent, freeze-drying powder injection etc.