how to solve the memory that increase by loadlevel

the memory is not to reduce if destroy gameobject and unload assetbundle or Resources.unloadUnuseAssets and so on,
is it a bug?

if i have too many levels and a lot of objects the memory will not enough

To make sure that the memory will be released, you can explicitly set all references to null. And then call System.GC().

The OnDestroy method can be really useful for that purpose:

public class MyClass : MonoBehaviour
    private Object reference1;
    private SomeOtherClass reference2;

    // ...

    void OnDestroy()
        this.reference1 = null;

        if (this.reference2 != null)
        this.reference2 = null;

i’m sure that all references to null,
and also used System.Gc.Collect();

but the memory not reduce equals it increased

i used
and Application.LoadLevel();

that i will say the memory is increased probability