When a state-owned enterprise is unable to pay off its debts, creditors may take the following measures:

1. Negotiate with state-owned enterprises: First, creditors can try to negotiate with state-owned enterprises and seek repayment solutions. State-owned enterprises can be required to provide repayment plans and supervise their implementation.

2. Bring a lawsuit: If negotiation fails, the creditor may bring a lawsuit to the court and demand the state-owned enterprise to fulfill its repayment obligations. In the course of litigation, it is necessary to provide relevant evidence to prove that state-owned enterprises do have debts.

3. Apply for enforcement: If the court decides that the state-owned enterprise must repay, but the state-owned enterprise still fails to perform its obligations, the creditor may apply to the court for enforcement. The court will take measures to implement the judgment, such as sealing up and auctioning the property of state-owned enterprises.

To sum up, when state-owned enterprises can't repay their debts, creditors can safeguard their rights and interests through negotiation, litigation and enforcement.

Legal basis:

Article 107 of the Contract Law of People's Republic of China (PRC) stipulates: "If a party fails to perform its contractual obligations or fails to perform its contractual obligations, it shall bear the liabilities for breach of contract such as continuing to perform, taking remedial measures or compensating for losses."

Article 236 of the Civil Procedure Law of People's Republic of China (PRC) stipulates: "A legally effective civil judgment or ruling must be fulfilled by the parties. If one party refuses to perform, the other party may apply to the people's court for enforcement. "