Below is the code for your reference(from fpdf.org).
If you want Big5 support, call this line in your script:
$pdf->AddBig5Font();
Then you can select the font like this:
$pdf->SetFont('Big5','',20);
All styles (bold, italic and underline) are available.
For GB:
$pdf->AddGBFont();
$pdf->SetFont('GB','',20);
All usual methods (Cell(), MultiCell(), Write() and GetStringWidth()) work with these new fonts.
Ex.php
require ('chinese.php');
$pdf=new PDF_Chinese();
$pdf->AddBig5Font();
$pdf->AddPage();
$pdf->SetFont('Big5','',20);
$pdf->Write(10,'zxc123你好');
$pdf->Output();