Can I keep the model value when click browser back button with angularjs?

Your scope will get cleared when you exit the page and recreated with the default values when you get back to it.

You have 2 options:

1. use a Service to keep this kind of information (like selectedItem from your dropdown) and other useful things. The option selected in the dropdown should be bound to the service object:

   angular.module('shared').factory('UsefulService', function() {
   
   var UsefulService = {};
   
   UsefulService.myPageSettings = {
       currentDropDownItem: 1, //this is what you need
       otherSetting: "blah"
   };
   
   return UsefulService;
   });
   

and in your controller you should bind the scope variable to it (don't forget to require the UsefulService in your controller's dependencies):

$scope.myDearSettings = UsefulService.myPageSettings;

and then access it with $scope.myDearSettings.currentDropDownItem;

2. you can set a hash on your route when the dropdown changes (bound to the value) so when you hit Back you will get to the same state because of the hash. Basically, the url in your address bar will look like: http://your_server:your_port/myPage#Today where Today is the selected item.

The most recommended solution is option #1.