$graph->title->SetFont(FF_SIMSUN,FS_NORMAL);
$graph->legend->SetFont(FF_SIMSUN,FS_NORMAL);
$graph->yaxis->title->SetFont(FF_SIMSUN,FS_NORMAL);
$graph->xaxis->title->SetFont(FF_SIMSUN,FS_NORMAL);你把字体设成FF_SIMSUN就可以了