使用ng-options就行啊
代码加载有些慢。。稍等一下可以看到效果：
http://codepen.io/flybywind/pen/GZyydY

template

<p ng-controller="MyCtrl">
    <select ng-model="province">
        <option value="">--province--</option>
        <option ng-repeat="p in provinces" value="{{p.value}}">{{p.text}}</option>
    </select>
    <select ng-model="city">
        <option value="">--city--</option>
        <option ng-repeat="c in citys" value="{{c.value}}">{{c.text}}</option>
    </select>
</p>

script

angular.module('myApp', [])
        .controller('MyCtrl', function ($scope) {
            $scope.province = '';
            $scope.city = '';
            $scope.citys = null;
            $scope.provinces = [
                {
                    value: 1,
                    text: 'jiangsu',
                    citys: [
                        {
                            value: 1,
                            text: 'nanjing'
                        }
                    ]
                },
                {
                    value: 2,
                    text: 'anhui',
                    citys: [
                        {
                            value: 1,
                            text: 'hefei'
                        }
                    ]
                }
            ];

            $scope.$watch('province', function (value) {
                if (!value) {
                    $scope.citys = null;
                } else {
                    $scope.citys = $scope.provinces.filter(function (p) {
                        return value == p.value;
                    })[0].citys;
                }
                $scope.city = '';
            });
        });

其实是我的问题，问题的解决根本是ng-model直接绑对象，然后option的value也绑相同的对象，这样就解决了'选中问题'，在后台取id或文本值，直接是对象的id或text。thanks！

在angularJS的官方文档上就有，需要自备梯子
下面是我用的1.4.7的版本的文档中的示例

<p ng-controller="ExampleController">
  <form name="myForm">
    <label for="repeatSelect"> Repeat select: </label>
    <select name="repeatSelect" id="repeatSelect" ng-model="data.repeatSelect">
      <option ng-repeat="option in data.availableOptions" value="{{option.id}}">{{option.name}}</option>
    </select>
  </form>
  <hr>
  <tt>repeatSelect = {{data.repeatSelect}}</tt><br/>
</p>

angular.module('ngrepeatSelect', [])
 .controller('ExampleController', ['$scope', function($scope) {
   $scope.data = {
    repeatSelect: null,
    availableOptions: [
      {id: '1', name: 'Option A'},
      {id: '2', name: 'Option B'},
      {id: '3', name: 'Option C'}
    ],
   };
}]);

结果就是option中显示的是name部分，model获得的是id，这里model用的是data.repeatSelect是因为循环是在option上，而导致作用域的不同