Jason.Bie said:

this method will add a cross line on the "deleted row", not really remove the row.

This is actually a by-default behavior caused by the igGrid's autoCommit option of the igGrid - that option is set to TRUE by default and thus provides batch updating. So the cross line indicates that that update is still not committed and can possibly be undone.
However, if you wish to have immediate updating (and row deleting in specific), you can simply set that option to FALSE and you'll be all set.

Jason.Bie said:

I want to know is there a way to remove rows from igGrid, 
also I don't want to user to see the updating styles like the delete button pops up when mouse on it.

There is not option about disabling the "delete"  button I'm afraid - setting the igGridUpdating feature's enableDeleteRow option to FALSE will also disallow row deleting.

Thus you need a custom solution. The one that I came up with is to hide the delete button whenever it may appear while you're hovering over the igGrid's records:

$("#grid1 tbody").hover(function() {
    $(".ui-iggrid-deletebutton").hide();
});

I've also attached a simple HTML sample to my reply in which you can see both of my suggestions in action.

Please let us know if there's anything else we can help you with.
All the best,
Borislav