Why gpu memory no release

when I remove primitive and destroyed,gou memory no release.

We’ll probably need a bit more info than that, but if you mean you created some data, then destroyed it, and are expecting your memory to change straight away, the short answer is that JS (and Chrome, from the icons) memory and garbage collection doesn’t work that swiftly, nor that straight forward. To release the memory, kill the tab that Cesium sits in. There’s all sorts of slow drip caching and more explicit limiters between the JS machine, Chrome and the WebGL layers (multiples).

Is there anything specific you’re trying to do? What sort of things are you doing, and what’s the expected behaviour vs. reality you’re reacting to?