简单说就是取地址，要详细嘛，打开delphi6\help\Del6op.hlp查@就行,The @ operatorThe @ operator returns the address of a variable, or of a function, procedure, or method; that is, @ constructs a pointer to its operand. For more information about pointers, see Pointers and pointer types. The following rules apply to @.If X is a variable, @X returns the address of X. (Special rules apply when X is a procedural variable; see Procedural types in statements and expressions.) The type of @X is Pointer if the default {$T杴 compiler directive is in effect. In the {$T+} state, @X is of type ^T, where T is the type of X. If F is a routine (a function or procedure), @F returns F抯 entry point. The type of @F is always Pointer.When @ is applied to a method defined in a class, the method identifier must be qualified with the class name. For example,@TMyClass.DoSomethingpoints to the DoSomething method of TMyClass. For more information about classes and methods, see Classes and objects.
The @ operator returns the address of a variable, or of a function, procedure, or method; that is, @ constructs a pointer to its operand. For more information about pointers, see Pointers and pointer types. The following rules apply to @.If X is a variable, @X returns the address of X. (Special rules apply when X is a procedural variable; see Procedural types in statements and expressions.) The type of @X is Pointer if the default {$T杴 compiler directive is in effect. In the {$T+} state, @X is of type ^T, where T is the type of X. If F is a routine (a function or procedure), @F returns F抯 entry point. The type of @F is always Pointer.When @ is applied to a method defined in a class, the method identifier must be qualified with the class name. For example,@TMyClass.DoSomethingpoints to the DoSomething method of TMyClass. For more information about classes and methods, see Classes and objects.
这方面 delphi 资料介绍的不多，它和c语言的&功能一样，你去查c
里面关于这个&符号的资料吧
If F is a routine (a function or procedure), @F returns F抯 entry point. The type of @F is always Pointer.When @ is applied to a method defined in a class, the method identifier must be qualified with the class name. For example,@TMyClass.DoSomethingpoints to the DoSomething method of TMyClass. For more information about classes and methods, see Classes and objects.
If F is a routine (a function or procedure), @F returns F抯 entry point. The type of @F is always Pointer.When @ is applied to a method defined in a class, the method identifier must be qualified with the class name. For example,@TMyClass.DoSomethingpoints to the DoSomething method of TMyClass. For more information about classes and methods, see Classes and objects.