Can anyone tells me the advantage and disadvantage for air prune 7 ft fig trees in recycle or reusable shopping bag for outdoor purposes ?
I heard it is much better than plant in container as this will avoid root bound.

Pacifica

Fabric containers prevent root circling and promote branching. The tree still outgrows the container though, and there is usually a mat of roots at the bottom that need to be sawed off when repotting. 
Pros:
Cool roots, the evaporation through the sides of the container keeps them cool, even in direct sun. If hot to the touch it is time to water.
Less work repotting.
Easy to drag large containers, no hard edges to catch on bumps.
Cheaper shipping than hard containers
Make your own with landscape fabric.
Use the trunks as handles (they are wood after all) container will not slide off assuming the tree is established.
Great for rooting, the extra air in the root zone means less chance of overwatering.

Cons:
Require more water
More likely to have dry spots in the root zone
More likely to dry in storage.
Not as nice looking.


http://rootpouch.com/faq

Thank you very much for your explanation. Can I use nylon material shopping bag as a fabric container s long as it is breathable ?

I used nylon feed sacks once and they broke down in the sun by the end of the season and it was a huge mess. Soft fabric shopping bags are usually made from PET or HDPE plastic and should last longer. Nylon is woven like a tarp, PET and HDPE are spun, they usually have dimples like a golf ball pressed in. 

7 ft is a lot of plant, hope you can find some big bags.

Hoosierbanana pretty much summed it up.  

here's where I got mine, they have 3 different kinds, I have the cheaper two.  They work just as advertised.  Some are 10+ gallon size.

https://www.greenhousemegastore.com/category/root-pouches

Here in Texas, I needed to make my mix a little more water retentive, they do dry out quickly, I still water daily.

Hi Don :  Thanks for the link. Do you think 20 gallon fabric pot is good enough to plant 7 ft fig tree ?

Pacific

Yes.  I have several 2 year old 7 footers in 15-20 gallon regular plastic containers, they just keep on growing.

I will say though, with the root pruning pots, I'm not sure how root pruning will go next year, or if it's even necessary as often.  Hopefully someone will chime in that has been growing in these for a long time.  This is my first year with them.

I have up- potted some of the 1 gallons I was growing in pouches and because I was trying not to disturb roots I had to cut them off, the pouches that is. 

Hi Don, Got you ! Thanks..............