the problem is solved

For starters, your radiation boundaries need to be atleast quarter wavelength above the patch antenna.
Also what is Sub3 in your simulation file?

I really didn't understand your problem. However, there are some things wrong with your design I guess:

1. Size of your coaxial feed -- the dimension you have taken (outer and inner) don't give you 50 ohm impedance. If air is the substrate between outer and inner conductor of a coaxial, the diameter would be D_outer = 2.3 mm and D_inner = 1 mm

2. There shouldn't be any ground layer where the coaxial enters (otherwise you are making a short). Therefore, increase your coaxial height between -14.5mm to -9 mm (along z axis) and remove the ground plane where the coaxial enters. [Please bear in mind that you should change the radius to the coax substrate to 1.15 mm as I told earlier]. Take a look at the figure.

3. draw coaxial outer conductor (you didn't have that). radius: 1.5 mm, height: from -14.5 mm to -9.5 mm.

4. change the circle radius (port1) to 1.5 mm.

5. define airbox as: Position: -70, -85, -14.5; xsize=140, ysize=170,zsize=40.

6. select the circle and define the waveport/lumped port.

7. I've simulated your structure and found the return loss curve which is attached here. (I used Hfss 11 version, you cannot open it in version 10).

Finally one general comment: when drawing 3-D figures, use draw box, draw cylinder etc. whereas you drew the polylines and connected them which is really tiring/ time consuming.

What is the advantage if we adding a coaxial outer conductor according to the above dimension?

A coaxial line should have an inner and an outer conductor. Since the airbox covers the coaxial feed, you need to define the outer conductor. Thickness of the outer conductor does not matter (I took it arbitrarily). If the material outside your coaxial substrate is electric (PEC), you don't need to define the outer conductor.

Thank you
I tried your method above and make the result. However, The return loss is too low, or S11(dB) too high. for example, the curve lines between -0.00001 to -0.00003

The curve is similar to you result instead of the S11 which is too high. How do I correct it? Is it my geometry still wrong?

Anyway, could you please send the file you do? I want to see what difference between your geometry and my geometry. If you have time, please convert it to HFSS version 10. Thank you.
My email address: ycfung27@netvigator.com

It means that your coaxial feed structure is not correct. There is no power going into the structure. Please take a look at example of Hfss how to define a lumped/wave port.
I would like to help you however, I don't have any option to change it to version 10. Anyway, I'm uploading the the design I made in version 11.