A method for preparing precise pattern of integrated circuits, which comprises the following steps: (S1) preparing a large pitch trench or circular through-hole structure with a hard mask in a first dielectric layer by lithography and etching; (S2) forming micro trench on the hard mask of the second dielectric layer at the bottom side wall of the trench or circular through-hole structure by plasma etching process; (S3) removing the first dielectric layer; (S4) opening the hard mask of the second dielectric layer at the micro trench formed on the hard mask of the second dielectric layer by plasma etching process; (S5) small pitch trench or circular through holes are prepared in the second dielectric layer.