Remove the "standard" WordPress post format.

no-standard-pf.php

<?php
/*
Plugin Name: No Standard Post
Description: Removes the standard post format.
Author: Christopher Davis
Author URI: http://christopherdavis.me
*/

add_action( 'add_meta_boxes_post', 'wpse41940_meta_boxes' );
function wpse41940_meta_boxes( $post )
{
    remove_meta_box(
        'formatdiv',
        $post->post_type,
        'side'
    );
    add_meta_box( 
        'wpse41940_formatdiv', 
        _x( 'Format', 'post format' ), 
        'wpse41940_format_meta_box', 
        $post->post_type, 
        'side', 
        'core' 
    );
}

function wpse41940_format_meta_box( $post, $box )
{
	if ( current_theme_supports( 'post-formats' ) && post_type_supports( $post->post_type, 'post-formats' ) ) :
	$post_formats = get_theme_support( 'post-formats' );

	if ( is_array( $post_formats[0] ) ) :
		$post_format = get_post_format( $post->ID );
		if ( !$post_format )
			$post_format = 'aside';
		if ( $post_format && !in_array( $post_format, $post_formats[0] ) )
			$post_formats[0][] = $post_format;
	?>
	<div id="post-formats-select">
		<?php foreach ( $post_formats[0] as $format ) : ?>
		<input type="radio" name="post_format" class="post-format" id="post-format-<?php echo esc_attr( $format ); ?>" value="<?php echo esc_attr( $format ); ?>" <?php checked( $post_format, $format ); ?> /> <label for="post-format-<?php echo esc_attr( $format ); ?>"><?php echo esc_html( get_post_format_string( $format ) ); ?></label><br/>
		<?php endforeach; ?><br />
	</div>
	<?php endif; endif;
}

add_filter( 'get_the_terms', 'wpse41940_filter_formats', 10, 3 );
function wpse41940_filter_formats( $terms, $post_id, $taxonomy )
{
    if( 'post_format' != $taxonomy ) return $terms;
    if( empty( $terms ) )
    {
        $aside = get_term_by( 'slug', 'post-format-aside', 'post_format' );
        // post formats are created as posts are saved in them.
        // so this is a bit of a hack
        if( $aside )
        {
            $terms[] = $aside;
        }
        else
        {
            $term = wp_insert_term( 'post-format-aside', 'post_format' );
            $terms[] = get_term( $term['term_id'], 'post_format' );
        }
    }
    return $terms;
}

sorry dear this is not good solution

make this by add_theme_support