Also when i edit field 1,2,3,4 from Child Object i want to copy that value in Main Object field 1,2,3,4.
What suggestion do you have for this problem?
You have some ways to solve it.
If the fields can be editable only in one object, you can use a Formula field.
If you want that these fields will be editable in both objects I suggest you to use a workflow rule, a flow or a Process Builder. Also, if you want to code, you can use a trigger for this.