Flexible SERS substrate based on small ball array and preparation method of flexible SERS substrate

The embodiment of the invention provides a flexible SERS substrate based on a small ball array and a preparation method of the flexible SERS substrate. The preparation method comprises the following steps: completely burying a small ball array formed on the surface of a hard substrate into a flexible substrate; carrying out soft and hard separation to obtain a flexible substrate with the small ball array, removing a part of the flexible substrate to expose the small ball array from the surface of the flexible substrate, and depositing an SERS active layer in the top area of the exposed small ball array. The method disclosed by the invention is simple and rapid in preparation process and good in controllability and repeatability; expensive micro-nano machining technologies such as traditional photoetching, electron beam photoetching and nanoimprint lithography are not needed, the number of layers of small ball arrangement does not need to be controlled, and the prepared flexible SERS substrate is large in area