构造运行之前骨干设立的结构。 初始化被称为结构的构造函数内。所以基本上，如果你需要之前骨干建立结构来增加任何东西，使用构造如果你需要骨干建立结构使用后增加任何初始化。

（从主体一个 Github上讨​​论）

What's the difference between initialize and constructor on a backbone model.

When I extend a backbone model (ParentModel) I use the initialize method to set any default properties. But whenever I create a Model based on the ParentModel I use the constructor to to run any intial functionality. I do this because it works but someone at work asked me why I use both initialize and constructor and I didn't have a good answer apart from it works. I could spend time reading though the source code to figure it out but it seemed much easier to ask here and get the right answer.

var ParentModel = Backbone.Model.extend({
  initialize : function() {
    // code here
  },
});


var Model = ParentModel.extend({
  constructor : function (options) {
    Backbone.Model.prototype.constructor.call(this, options);
    // code here
   },

constructor runs before Backbone sets up the structure. initialize is called inside the structure's constructor function. So basically if you need to augment anything before Backbone sets up the structure, use constructor if you need to augment anything after Backbone sets up the structure use initialize.

(from a Github discussion on the subject)