No. You should not add them together. There are several reasons that you may have received two Forms W-2.
One reason could be that one of the forms is a corrected Form W-2. Does the amount in Box 1 reflect your annual salary (refer to your last pay statement)? If it does, then look for the "Corrected" box at the top of the form to see if it is checked. If it is, you should enter the corrected Form W-2 into TurboTax and keep the other one for your records.
Another reason is that you may have worked in separate states for the same employer (Box 15 of the Form W-2), and the amount or blank entry in box 1 may reflect the amounts you earned in each state.
If you still cannot discern the reason you received two Forms W-2, it is suggested that you confer with your employer before entering the amounts into TurboTax. Forms W-2 are furnished to the Internal Revenue Service, so you want to ensure they match its records.