An acid salt of a compound represented by general formula, wherein: R a is selected from hydrogen or methyl; R 1 is selected from hydrogen, fluorine, chlorine, bromine or methyl; R 3 is selected from hydrogen, amino, hydroxyl, fluorine, chlorine, methyl, -S(CH 3) or trifluoromethyl; R 4 is selected from hydrogen, amino, hydroxyl, fluorine, chlorine, -N(CH 3) 2, -NH(CH 3) or fluorine; R 5 is selected from hydrogen, fluorine, chlorine, bromine, methyl, ethyl, propyl or isopropyl; R 6 is selected from hydrogen, fluorine, chlorine, bromine, methyl, ethyl, propyl or isopropyl; R 7 is selected from hydrogen, fluorine, chlorine, bromine or methyl; acid in the acid salt is selected from hydrochloric acid, sulfuric acid, nitric acid, hydrobromic acid, hydrofluoric acid, hydroiodic acid, phosphoric acid, 2,5-dihydroxybenzoic acid, 1-hydroxy-2-naphthoic acid, acetic acid, ethanesulfonic acid, dichloroacetic acid, trichloroacetic acid, acetohydroxamic acid, adipic acid, benzenesulfonic acid, 4-chlorobenzenesulfonic acid, benzoic acid, 4-acetylaminobenzoic acid, 4-aminobenzoic acid, capric acid, caproic acid, octanoic acid, cinnamic acid, citric acid, cyclamic acid, camphor sulfonic acid, aspartic acid, camphoric acid, gluconic acid, glucuronic acid, glutamic acid, isoascorbic acid, lactic acid, malic acid, mandelic acid, pyroglutamic acid, tartaric acid, dodecyl sulfuric acid, dibenzoyl tartaric acid, 1,2-ethanedisulfonic acid, ethanesulfonic acid, formic acid, fumaric acid, galactonic acid, gentisic acid, glutaric acid, 2-ketoglutaric acid, glycolic acid, hippuric acid, hydroxyethyl sulfonic acid, lactobionic acid, ascorbic acid, aspartic acid, lauric acid, camphoric acid, maleate acid, malonic acid, methanesulfonic acid, 1,5-naphthalene disulfonic acid, naphthalene-2-sulfonic acid, nicotinic acid, oleic acid, orotic acid, oxalic acid, palmitic acid, pamoic acid, propionic acid, salicylic acid, 4-aminosalicylic acid, sebacic acid, stearic acid, succinic acid, thiocyanic acid, undecylenic acid, trifluoroacetic acid, benzenesulfonic acid, p-toluenesulfonic acid or L-malic acid; preferably hydrochloric acid, phosphoric acid, ethanesulfonic acid, benzenesulfonic acid, methanesulfonic acid, fumaric acid, hydroxyethyl sulfonic acid, oxalic acid or hydrobromic acid. R a is selected from hydrogen or methyl; R 1 is selected from hydrogen, fluorine, chlorine, bromine or methyl; R 3 is selected from hydrogen, amino, hydroxyl, fluorine, chlorine, methyl, -S(CH 3) or trifluoromethyl; R 4 is selected from hydrogen, amino, hydroxyl, fluorine, chlorine, -N(CH 3) 2, -NH(CH 3) or fluorine; R 5 is selected from hydrogen, fluorine, chlorine, bromine, methyl, ethyl, propyl or isopropyl; R 6 is selected from hydrogen, fluorine, chlorine, bromine, methyl, ethyl, propyl or isopropyl; R 7 is selected from hydrogen, fluorine, chlorine, bromine or methyl; acid in the acid salt is selected from hydrochloric acid, sulfuric acid, nitric acid, hydrobromic acid, hydrofluoric acid, hydroiodic acid, phosphoric acid, 2,5-dihydroxybenzoic acid, 1-hydroxy-2-naphthoic acid, acetic acid, ethanesulfonic acid, dichloroacetic acid, trichloroacetic acid, acetohydroxamic acid, adipic acid, benzenesulfonic acid, 4-chlorobenzenesulfonic acid, benzoic acid, 4-acetylaminobenzoic acid, 4-aminobenzoic acid, capric acid, caproic acid, octanoic acid, cinnamic acid, citric acid, cyclamic acid, camphor sulfonic acid, aspartic acid, camphoric acid, gluconic acid, glucuronic acid, glutamic acid, isoascorbic acid, lactic acid, malic acid, mandelic acid, pyroglutamic acid, tartaric acid, dodecyl sulfuric acid, dibenzoyl tartaric acid, 1,2-ethanedisulfonic acid, ethanesulfonic acid, formic acid, fumaric acid, galactonic acid, gentisic acid, glutaric acid, 2-ketoglutaric acid, glycolic acid, hippuric acid, hydroxyethyl sulfonic acid, lactobionic acid, ascorbic acid, aspartic acid, lauric acid, camphoric acid, maleate acid, malonic acid, methanesulfonic acid, 1,5-naphthalene disulfonic acid, naphthalene-2-sulfonic acid, nicotinic acid, oleic acid, orotic acid, oxalic acid, palmitic acid, pamoic acid, propionic acid, salicylic acid, 4-aminosalicylic acid, sebacic acid, stearic acid, succinic acid, thiocyanic acid, undecylenic acid, trifluoroacetic acid, benzenesulfonic acid, p-toluenesulfonic acid or L-malic acid; preferably hydrochloric acid, phosphoric acid, ethanesulfonic acid, benzenesulfonic acid, methanesulfonic acid, fumaric acid, hydroxyethyl sulfonic acid, oxalic acid or hydrobromic acid.