Exhibit 16.1

Armanino LLP

2700 Camino Ramon

Suite 350

San Ramon, CA 94583-5004

925 790 2600 main

925 790 2601 fax

armanino.com

July 27, 2023

Securities and Exchange Commission 100 F Street N.E.

Washington D.C. 20549

Commissioners:

We have read item 4.01 of Form 8-K of ACM Research, Inc dated July 27, 2023, and agree with the statements concerning our firm contained therein. We have no basis to agree or disagree with other statements of the registrant contained herein.

Armanino LLP

San Ramon, California