Is it necessary for state-owned enterprises to have more than 50% state shares?

There is no such rule.

In 1994, the Interim Measures for the Administration of State-owned Equity of Limited by Share Ltd stipulated that:

State-owned equity holding is divided into absolute holding and relative holding. Absolute holding means that the proportion of state-owned shares exceeds 50% (excluding 50%); Relative holding means that the proportion of state-owned shares is higher than 30% and lower than 50%, but due to the decentralization of equity, the state has a controlling influence on joint-stock companies.

Large companies, such as listed companies with more than 5%, can also be regarded as state holding, that is, state holding, and the state has great control over the company's operation.