One is the invention priority principle, and the other is the application priority principle.
The principle of prior invention means that if two or more people file a patent application for the same invention, the patent right shall be granted to the person who made the invention first, regardless of the time when he filed the patent application. However, when adopting this principle, we often encounter many practical difficulties in determining who is the first inventor. Therefore, at present, only a few countries in the world, such as the United States, Canada and the Philippines, have adopted this principle.
The so-called principle of prior application means that when two or more people apply for the same invention separately, they don't ask the time when they made the invention, but the time when they filed the patent application shall prevail, that is, the patent right is granted to the first applicant, which is the practice adopted by most countries in China and the world.