The invention aims to provide a method for synthesizing high-added-value alkyl pyrroles from methanol and ammonia by a one-step process. The method is characterized in that a non-equilibrium plasma-catalyst coupled mode is adopted to activate the raw materials methanol and ammonia so as to obtain the alkyl pyrroles. The method has the advantages of cheap and accessible reaction raw materials, mild reaction conditions, and simple and convenient operating technique. The conditions can be further regulated to synthesize methyl isonitrile, N,N-dimethyl cyanamide, aminoacetonitrile, N,N-dimethyl aminoacetonitrile and the like. The invention provides a novel method for preparing high-added-value chemicals by converting methanol. Besides, the method is suitable for synthesizing high-added-value nitrogenous compounds from one or two of methanol, ethanol and propanol and ammonia gas in the presence of the dielectric barrier plasma and catalyst.