The Russian club also have the option to sign Moses permanently for £8million when his loan comes to an end.
The Nigeria international, 29, who spent the second half of the 2019-20 season at Inter Milan, was surplus to requirements at Chelsea and needed to be sent out on loan again.
‘It’s a great pleasure for me to sign for Spartak,’ Moses said after his move was confirmed.
‘They are one of the greatest clubs in Europe. I can’t wait to get started and meet my team-mates. It’s going to be an interesting season.’
Moses who enjoyed a successful season during Conte’s reign with the manager converting him to a right wing-back, made his last appearance in a Blue shirt in September 2018.
The move to Spartak Moscow marks his sixth spell away from Stamford Bridge after joining the club in 2012.