Dear All, 
I am writing this post in order to find a solution for my wife's visa which has been rejected recently. I am an Iranian student in Germany and I have been here since March 2017. I applied for my student visa on 8th of January 2017 and she applied for her Spouse visa on 8th of February 2017. On 26th of June, she received a letter which mentioned that her visa has been rejected because I as her husband could not prove that I can support her financially. however, we provided an official bank statement letter that presented we have a sufficient amount of money (20 thousand euro) when we applied for our visas.  
how can we solve this problem?
 

Hello,

Can you please tell me that the Bank statement with 20,000. euros was from your Iranian Bank Acount or the German Bank Account?

Also please inform how long is your course of study?

Regards, Raj++

At that time, We presented 20000 in 2 separated accounts during our interview, One bank account with 10K euro for me and one 10K euro for my wife.  These two accounts were from Iranian bank.
Now I am doing my master program for 2 years. 

Hi,

it would have been better if you had the money in your German bank account. 

1- Money
For example for a 2 years Master course and a stay of 2 years for your wife the calculation is as follows;

2 x 700 euros per person/ per month = 1400 euros per month for both of you

1400 euros x 24 months = 33,600. euros in total

This is offcourse an upper limit, one can always argue that the living costs for the second person will be reduced as they share the same apartment. 

2- Apartment Contract
In that case you must have a rental agreement for a family room in your dormitory or a private 1/2-room apartment larger than 30m2.

3- Health Insurance 
A tentative health insurance for your wife will be helpful 

4- Letter from University 
A letter from University might be helpful, explaining your registration for the course of study, the duration and how student-family life balance is important etc....

5- Iranian Documents
If your wife has done Bachelors or German language courses and/or any properties or family Business or support documents to show strong ties with Iran and that she must return to Iran due to these ties.

Once you fulfill these requirements you can file a Family Visa for your wife. Given the experience with my peers, the chances are very low.

Good luck and keep us posted.

regards, Raj++

P.S: this is not a legal advice!