Armstrong has been banned from cycling and lost all of his seven Tour de France titles after the United States Anti-Doping Agency released a report that accused him of running the most sophisticated doping programmes that the sport had ever seen.
However, Contador, who has served a two-year ban for doping offences, has leapt to the defence of 41-year-old Armstrong.
"He is being humiliated and lynched, in my opinion. He is being destroyed," said Contador. "At certain times and places Lance is not being treated with any respect.
"Right now people are talking about Lance but there has not been any new test or anything.
"It's based exclusively on witness statements that could have existed in 2005. What I do know is that if cycling is popular in the United States it is thanks to him."
Contador won the tour in 2007 and 2009.