<li ng-repeat="a in b">
{{a.id}} //Here is the loop array to get the id
<ul>

<li ng-repeat="c in a.arr">{{c.name}}</li> //这里该怎么循环出arr的name？

</ul>
</li>

Isn’t this okay?

<li ng-repeat="a in b">
    <a>{{a.id}}</a> 
    <ul>
        <li ng-repeat="c in a.arr">{{c.name}}</li>
    </ul>
</li>

$scope.b=[
        {"id":1,
            "ps":1,
            "arr":[{"name":2,"user":13},{"name":3,"user":24}]
        },
        {"id":2,
            "ps":2,
            "arr":[{"name":4,"user":34},{"name":5,"user":45}]
        }
    ]

<li ng-repeat="a in b">
    <a>{{a.id}}</a>
    <ul>
        <li ng-repeat="c in a.arr">{{c.name}}</li>
    </ul>
</li>