NOVELTY - Preparing quinazoline derivatives (I), comprises reacting 6,7-bis(2-methoxyethoxy)quinazolin-4(3H)-one (II) with 3-ethynylaniline compounds (III) in an organic solvent in presence of an organic alkali and a peptide condensing agent.    USE - The method is useful for preparing (I) e.g. erlotinib.    ADVANTAGE - The method: utilizes easily available low cost raw material; has mild reaction condition, less side reaction, high product yield and less environmental pollution; and is suitable for large scale production.    DETAILED DESCRIPTION - Preparing quinazoline derivatives of formula (I), comprises reacting 6,7-bis(2-methoxyethoxy)quinazolin-4(3H)-one (II) with 3-ethynylaniline compounds of formula (III) in an organic solvent in presence of an organic alkali and a peptide condensing agent.    R1 = H, SiR1R2R3, dimethylmethanol-1-yl or compound of formula ();    R1, R2, R3, R4, R5, R6 = 1-8C alkyl, 2-8C alkenyl, 2-8C alkynyl, 3-8C cycloalkyl, 2-8C saturated heterocyclic group, 6-12C aryl or 3-12C heteroaryl (all are optionally substituted by A);    A = F, Cl, Br, I, OH, protected OH, nitro, cyano, amino, protected amino, carbonyl, sulfo-carbonyl, -NH-(T), bi(1-12C alkyl)-substituted amino, bi(6-12C aryl)-substituted amino, bi(3-12C heteroaryl)-substituted amino, -O-(T), -C(=O)-(T), -CONH2, -CONH-(T), -OCO2-(T), -OCONH2, -OCONH-(T), -NHC(=O)-(T), -NHCO2-(T), -NHC(=O)NH2, -NHC(=O)NH-(T), -NHC(=S)NH2, -NHC(=S)NH-(T), -NHC(=NH)NH2, -NHC(=NH)NH-(T), -NHC(=NH)-(T), -C(=NH)NH-(T), -S(=O)-(T), -SO2NH2, -SO2NH-(T), -NHSO2-(T), -CH2NH2, -CH2SO2CH3, 6-12 aryl, 6-12 aryl-substituted 1-12C alkyl, 3-12C heteroaryl, 3-12C heteroaryl-substituted 1-12C alkyl), 3-12C saturated heterocyclic group, 3-12C unsaturated heterocyclic group, 3-12C cycloalkyl, alkoxy-substituted 1-12C alkyl, methoxyphenol, methoxy-ethyl, mercapto or -S-(T) (where number of substituent group A is 1-3 or more than three); and    T = 1-12C alkyl, 2-8C alkenyl, 2-8C alkynyl, 3-12C cycloalkyl, 6-12C aryl, 3-12C heteroaryl, 3-12C saturated heterocyclic group or 3-12C unsaturated heterocyclic group.