To verify a trade company in Linghai, a process similar to the one for verifying companies in general follows these steps:

1. **Official Registration**: Verify that the company has legally registered with the local administrative authority (such as the Bureau of Industry and Information). This will provide their unique registration number.

2. **Company Database Check**: Conduct an online search through official government databases, such as the China Enterprise Information System (CEIS), to verify the company’s information.

3. **Verifying Trade Documents**: Request and check relevant trade documents like business licenses, import/export permits, or tax certificates. These documents should confirm the company’s trade status.

4. **Industry Expert Consultation**: If necessary, consult with industry experts or professionals in Linghai who are familiar with local trade regulations. They can provide additional insights to verify the company’s credibility.

Remember, the verification process might vary depending on specific regulations and requirements in Linghai.