The invention provides an ionic-like liquid and a preparation method and an application thereof in preparation of alkylated oil. An amide compound undergoes a reaction with a first metal compound and more than one second metal compound to obtain the ionic-like liquid. With the ionic-like liquid as a catalyst, isoparaffin and olefin are subjected to an alkylation reaction, the ionic-like liquid is separated, and thus the alkylated oil is prepared. The ionic-like liquid has the advantages of easily obtained synthetic raw materials, simple synthetic method and cheap price, the alkylation reaction with the ionic-like liquid as the catalyst has high selectivity, and the proportion of C8 components and trimethyl pentane and the octane number of the alkylated oil are both greatly improved.