Dayi, formerly known as Menghai Tea Factory, belonged to China Tea Yunnan Branch in the planned economy era, and was restructured into a private joint-stock company in 2005.

The Dayi brand trademark we see now is registered by Menghai Tea Factory with the registration number 1989. Prior to this, the products of Menghai Tea Factory uniformly used the trademark of "China Tea", but this "Old No.8 Middle School" was common to all enterprises of China Tea Company, and many products of small garbage factories also used this trademark. Therefore, Menghai Tea Factory had foresight, and after that, it registered and used a new trademark, so did China Tea.

China tea brand that came back after 2006 is already the brand of COFCO (that is, COFCO in Fulinmen).