Cain Velasquez was recently moved into his new home for the foreseeable future -- Wasco State Prison -- where he posed for a brand new mugshot ... which TMZ Sports has obtained.

Velasquez, 42, who was sentenced to five years in prison for attempted murder on March 24, was transferred from the county jail near San Jose to the Cali state prison in Wasco.

When the UFC legend arrived, prison officials ordered Velasquez to pose for another mugshot ... and he appears serious and stoic.

The pic was snapped just over three years after he was first arrested (and stood for a mug) for attempting to shoot a man named Harry Goularte.

Goularte is accused of molesting one of Cain's family members ... and is himself due in court this year, where he's facing serious criminal charges.

Cain expressed remorse in front of a judge before sentencing in a courthouse late last month ... saying he understood he screwed up, and would do all he could to make ammends.

It must've worked ... 'cause Velasquez, who was facing decades behind bars, received a five-year sentence ... in spite of Goularte's relatives asking for more serious time.