How to get my husbands real income who lives in us?

You can try to get the proper details of his salary through your own sources. 

The court will go by the evidences of his salary produced by him. 

You only have to prove that they are manipulated or fabricated. 

You can't obtain any details through court and the court will not entertain your imaginary thoughts in this regard. 

Thank you for you reply Sir. I have his 4 year old salary slips. But I cannot access his latest salary. As per his affidavit, his salary is less than half of what it was 4 years ago. He is clearly lying.

What other document or proof should I collect to prove he is fabricating his salary? I emailed his company but they are not disclosing his salary. If I get an approximate salary range through his friends, can I use that to file a case against him for full investigation? 

Is there any helpline from Indian Government or US Embassy to help women whose husbands cheat them and escape to another country?

You cannot prove his salary by any hearsay evidence. 

You can tell before the court that he was drawing this salary 4 years ago and his salary cannot be reduced over the passage of time. 

It depends on how strongly you present your argument in the case