How to deal with the five-bit utf encoding in the Chinese language obtained by Mysql?

What should I do if Mysql uses 5-bit utf encoding in Chinese? Using php to retrieve mysql values, we can see on the webpage that Chinese is a 5-bit utf8 code, not a Chinese text. what is the problem? Mysql runs show & nbsp; variables & nbsp; like & nbsp; '% char %'. The result is as follows: what should I do if the Chinese character obtained by character_s Mysql is 5-bit utf encoding?
Use php to obtain the mysql value. on the webpage, the Chinese character is UTF-8 encoded, not a Chinese character.
What is going on?

Mysql runs show variables like '% char %'. The result is as follows:
Character_set_clientutf8
Character_set_connectionutf8
Character_set_databaseutf8
Character_set_filesystembinary
Character_set_resultsutf8
Character_set_serverutf8
Character_set_systemutf8

Written in php
$ Conn = mysql_connect ("localhost", "root", "1 ");
Mysql_select_db ("123", $ conn );
Mysql_query ("set names 'utf8 '");
$ SQL = "select * from 123.abc ";
$ Result = mysql_query ($ SQL );
$ Res1 = mysql_fetch_array ($ result, MYSQL_NUM );
Echo json_encode ($ res1 );
Mysql_close ($ conn );
------ Solution --------------------
\ U4e2d?

This is the result of json_encode processing and does not affect the use of php and js.
It is still a Chinese character before json_encode.