On March 15, the management department of gem company of Shenzhen Stock Exchange issued a letter of concern to Zhengzhou Sino-Crystal Diamond Co.Ltd(300064) asking the company to explain the specific contents and detailed process of communication, negotiation and cooperation with Zhonghua firm; Combined with the differences between the audit fees in 2021 and those in previous years, this paper discusses in detail the specific basis of “the increase of audit fees is mainly due to the tight audit time and heavy tasks of the company’s financial report in 2021, which requires more manpower and energy from the audit institutions”, and the differences between the manpower arrangements proposed by Zhonghua affairs and the relevant arrangements with the audit institutions in previous years; Whether the company has purchased audit opinions.