Look at the packaging
The first thing is to look at all the information given on the package, whether there are factory names, addresses, registered trademarks and anti-counterfeiting marks. See if the package is intact and there are no traces of secondary use.
smell
Real latex paint has a faint fragrance and a taste similar to earth. The muddy smell of fake latex paint is pungent or tasteless.
Wipe.
Really latex paint is particularly delicate and lubricated. Fake latex paint has astringency and graininess.
Brush it.
True latex paint is smooth to brush and has strong hiding power. Fake ones have no hiding power, and dry ones have little hardness.