Hello,
Are you trying to retrieve the sheet data along with the spreadsheet? You should be able to set $optParams.includeGridData to true:
$sheets->spreadsheets->get($sheetId, ['includeGridData' => true]);
Alternatively, if you're trying to list all the sheets in your account, you may use the Drive API to list files with a query:
$client = new Google_Client();
$drive = new Google_Service_Drive($client);
$sheetsList = $drive->files->listFiles([
'q' => "mimeType='application/vnd.google-apps.spreadsheet'",
'fields' => 'nextPageToken, files(id, name)'
]);
For this latter option, refer to the API reference for a full detailing of available options.

i want to get this sheetname, not spreadsheet file.
i do $sheets->spreadsheets->get($sheetId, ['includeGridData' => true]); but it only return this

You can find this value at sheets[sheet_index].properties.title.
Most helpful comment
Hello,
Are you trying to retrieve the sheet data along with the spreadsheet? You should be able to set
$optParams.includeGridDatatotrue:Alternatively, if you're trying to list all the sheets in your account, you may use the Drive API to list files with a query:
For this latter option, refer to the API reference for a full detailing of available options.