Time-resolved X-ray measurements using x-ray framing cameras are an important means of diagnosing inertial confusion experiments.Camera systems Includes three parts:photocathode,MCP multiplier and phosphor screen,and photocathode gain is one of important performance parameters of the whole system that is we committed to study.It has been specifically studied the production of Csl cathode technology,but Csl easy to absorb moisture,so it is mainly used in closed system.In this paper we studied the photocathode quantum efficiency of Au used in opening framing tube.The idea in this article is to raise the initial photoelectron number in order to enhance the gain of the system.We use some different ways to coat cathode on the one MCP in order to reduce the impact of different substrate.Firstly we coated different thickness of Cu film and Au film.