Taking check box option and turn into select list I want to take the value of multiple checkbox options while creating node and then when viewing the node, I want these values which were selected in a multiple checkbox to be in a select list.

Any idea how to implement this?
you could do that in your module, try to implement hook_node_view and get the values of the node variable, and then do your changes.

Im pretty sure you dont want to save those values from the select list, just show it in an another matter, no?