I'm building an easy app for chatting, each time I type in a sentence, the sentences is added into an array(which used to load the table view in cellForRowAtIndexPath delegate method), then I reload the table view. At last I use the following code to scroll the table view to the bottom if ([self.chatList numberOfRowsInSection:0] != 0) { NSUInteger rowCount = [self.chatArray count]; NSIndexPath* indexPath = [NSIndexPath indexPathForRow:rowCount-1 inSection:0]; [self.chatList scrollToRowAtIndexPath:indexPath atScrollPosition:UITableViewScrollPositionTop animated:YES]; } however, the table view sometimes performs well, sometimes only scrolls to the second to the last line……