my $xl = Spreadsheet::ParseExcel->new;  # or whatever module/version works
my $wb = $xl->Parse( $filepath ) or die "$filepath: $!\n";

for my $sheet ( @{$wb->{Worksheet}} ) {
    $sheet->{MaxRow} ||= $sheet->{MinRow};
    for my $row ( $sheet->{MinRow} .. $sheet->{MaxRow} ) {
        $sheet->{MaxCol} ||= $sheet->{MinCol};
        for my $col ( $sheet->{MinCol} .. $sheet->{MaxCol} ) {
            my $cell = $sheet->{Cells}[$row][$col];
            my $val = $cell->{Val};

            if ( $cell->{Code} eq 'ucs2' ) {
                $val = decode( "UTF-16BE", $val );

                if ( $val =~ /\p{Han}/ ) {
                    # this cell contains Chinese characters
                }
                # NB: there may be non-ASCII Unicode characters that are not Chinese
            }
        }
    }
}