The present invention relates to a new preparation method for escitalopram pamoate ((S)-(+)-1-[3-(dimethylamino)propyl]-1-(4-fluorophenyl)-1, 3-dihydro-5 cyanoisobenzofuran pamoate), wherein the method is environmentally friendly and pollution-free, and the escitalopram pamoate prepared by means of the method has a high purity and a good repeatability.