I want to load external swf in movieclip and next external swf should load Automatically

in as3 you use the loader class (not movieclips) to load external swfs.

you can use an Event.COMPLETE event listener (applied to the loader's contentLoaderInfo property) to check when loading is complete and start the next swf loading.

you can use the loader's content property (caste as a movieclip) to determine info (including totalFrames) about the loaded swf's main timelnie (once loading is initialized, for the totalFrames, or complete, for some other properties like height and width).

var loader:Loader=new Loader();

loader.contentLoaderInfo.addEventListener(Event.COMPLETE,loadcompleteF);

loader.load(new URLRequest("swf1.swf"));

var loadedSWF:MovieClip;

function loadcompleteF(e:Event):void{

loadedSWF=MovieClip(loader.content);

trace(loadedSWF.totalFrames);

}