How to check the novelty of patent?

Not accurate. There are relative standards and absolute standards to judge novelty. The relative standard is whether it is disclosed only in the country and region where the patent is applied, and the absolute standard is whether it is disclosed globally.

According to the second paragraph of Article 22 of China's Patent Law, whether it is novel or not depends on whether the patent has neither existing technology nor conflicting applications. The prior art adopts absolute standards. Conflict application means that the application for a patent for invention or utility model is not filed before the filing date, but after the filing date (including the filing date).

I hope I can help you.