The app work fine on iPhone 6s(iOS 9),however,quit on iPhone 5(iOS8).And all infomation I can get only this:
When Xcode showed this the Xcode exit immediately so I can see nothing in console.
Hope someone can give me some advice to avoid this.Thanks in advance.

This is happen when there is a lot of memory pressor while our app is running on device(Generally you will not face this issue in simulator).
This method is called when you receive memory warning.
In this method you can release any unused resources, objects, etc. to free up memory.
You can use xcode tool called intrument by pressing command + i. There are lot of options available to check memory leaks, memory allocations, etc.
So use memory allocation tool to check allocation and deallocation of memory when your app is running on device.
This will help you to overcome this issue.