查了查手册，发现：smarty连接字符串通过的是关键字：|cat:

例如：

index.php:

$smarty = new Smarty; 

$smarty->assign('articleTitle', "Psychics predict world didn't end");

$smarty->display('index.tpl');

index.tpl:

{$articleTitle|cat:" yesterday."}

OUTPUT:

Psychics predict world didn't end yesterday.

{assign var="h_index" value=$cur_yearmonth.year|cat:"-"|cat:$cur_yearmonth.mon|cat:"-"|cat:$day.day }