If you want to draw a 3D polyline to connect the dots try this:
In excel get your data in x,y,z format. This can be done by creating an equation to concatenate the data; e.g =A1&","&B1","&C1 where cells A1, B1 and C1 hold the x, y and z values. Highlight the new column and press Ctrl+C (copy). In autocad start the 3dpoly command, when it prompts you for a start point, paste the coordinates (Ctrl+V) at the command line.