我找到了一种方法，将行从控制器传递给模型。
产品型号：

public function getFieldAmountTotal($rowArray, $fieldNames){
        // Can't use recursive -1 because it includes current filtering
        // This will only grab the total by id
        // Can't not pull id because filtering on related tables
        //$totalAmounts = $this->find( 'all', array('fields' => $fieldNames));
        $totalAmounts = $this->find( 'all', array('fields' => $fieldNames, 'group' => 'MovieStar.id'));
        $grandTotal = array();
        foreach($fieldNames as $fieldName){
                $grandTotal[$fieldName] = 0;
        }
        //foreach($totalAmounts as $amount){
        foreach($rowArray as $thisRow){
            foreach($fieldNames as $fieldName){
                    $grandTotal[$fieldName] += $thisRow['MovieStar'][$fieldName];
            }
        }
        debug('$grandTotal');
        debug($grandTotal);
        return $grandTotal;
    }

控制器：

$this->Prg->commonProcess();
        $this->paginate = array( 'conditions' => $this->MovieStar->parseCriteria($this->Prg->parsedParams()), 'limit' => 100);
        $movieStars = $this->paginate();

        // Get total amounts for stars
        $amountFields = array('amount','loss_axis', 'loss_mgr1', 'loss_mgr2', 'loss_rep');
        $reject_totals = $this->MovieStar->getFieldAmountTotal($movieStars, $amountFields);

结果：

array(
    'amount' => (float) 4074.97,
    'loss_axis' => (float) 22,
    'loss_mgr1' => (float) 0,
    'loss_mgr2' => (float) 0,
    'loss_rep' => (float) 0
)