To study the chemical constituents of the herbaceous stems of Ephedra intermedia Schrenk et C.A.Mey.Twenty-two compounds were isolated from the 50% aqueous acetone extract of Ephedra intermedia by silica gel,sephadex LH-20 column chromatography,Toyopreal HW-40C column chromatography,as well as semi-preparative HPLC methods.Their structures were identified by spectral analysis as 4-methoxycinnamic acid (1),cinnamic acid (2),ω-hydroxypropioguaiacone (3),threo-8S-7-methoxysyringylglycerol (4),3-(2,4′-dihydroxy-3′,5′-dimethoxyphenyl)propanoic acid (5),8-hydroxy-9-methyl-7-(4-hydroxy-3,5-dimethoxyphenyl)-7-propanone (6),3-hydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)-1-propanone (7),2-hydroxyl-1-［4-hydroxy-3-methoxyphenyl(propan-1-one)］ (8),methyl caffeate (9),trans-syringin (10),cis-syringin (11),(4R)-4-hydroxy-4-(2-hydroxypropan-2-yl)cyclo-hex-1-ene-1-carboxylic acid (12),7-hydroxyterpineol (13),dehydrovomifoliol (14),abscisic acid (15),loliolide (16),(E)-3-(3-hydroxybut-1-enyl)-2,4,4-trimethylcyclohexa-2,5-dienone (17),3-(3′-hydroxybutyl)-2,4,4-trimethylcyclohexa-2,5-dienone (18),4-isopropyl benzoic acid (19),p-cymen-7-yl β-D-glucopyranoside (20),acyclic 7-hydroxygeranic acid (21),7,7-dimethylbicyclo［3.1.1］hept-2-ene-1-carboxylic acid (22).And compounds 3-6,8,10-14,17-19,21 and 22 are isolated from this plant for the first time.The results of their anti-asthma activities showed that compounds 11,14 could significantly inhibit the release of β-aminohexosidase.