To verify a trade company in Changchun, China, you would follow these steps:

1. **合法性确认**: Start by ensuring that the company is registered and operates legally within Changchun. You can check official government databases like the ‘Changchun Business Information Query System.’

2. **Registration verification**: Obtain the company’s registration number, which usually appears on their business license or tax certificate. You can also visit local administrative bureaus to verify the registration details.

3. **Company background research**: Conduct a thorough search for the company online. Verify their website, social media profiles, and any other public information sources.

4. **Industry reputation**: Check if the company is well-regarded within their industry in Changchun. This can be done through networking or by referring to industry publications.

By following these steps, you will have a comprehensive verification process for a trade company in Changchun.