The invention discloses a preparation method of a double-sided copper-clad LCP plate, and the method comprises the following steps: S1, placing stacked stacks flat on a lower pressing plate of pressing equipment; S2, sequentially pre-pressing, pressurizing and maintaining the stacks by using the pressing equipment to obtain a semi-finished product; and S3, performing air cooling treatment on the semi-finished product to obtain a finished product. Compared with the double-sided copper-clad LCP plate prepared by adopting a wire pressing method in the prior art, the double-sided copper-clad LCP plate prepared by adopting a surface pressing method has higher binding force, better welding resistance, higher peeling strength and better structural stability. The shape appearance and flatness of the LCP plate can be improved.