In Yii 2.0 Framework's view，cannot use $this->registerCssFile() to register css file. After debug I found it's because not add head() flag in layout file, after add head() into layout, css is register like before

{ registerCssFile }

//views/site/index.php

$this->registerCssFile($this->theme->baseUrl.'/plugins/bootstrap-table/bootstrap-table.min.css', [[View::POS_HEAD]]);

{ add Head flag}

//views/layout/main.php

<header>

...

<?php $this->head(); ?>
</header>