The 21-year-old striker will join fellow Boro team mate Adam Reach, also on loan, at New Meadow and could be considered when the Shrews host Coventry at the weekend.
Main began his career at Darlington before making the short trip down the A66 where he scored 5 times in 25 appearances for Tony Mowbray's men prompting Graham Turner to secure the young forward's temporary signature.
"We've bolstered the squad now with Curtis and he's a very exciting prospect to have in our ranks," the Shrews boss told the club's official website.
"He's been in and around the first team at Middlesbrough for a couple of years and having allowed us to take Adam Reach and been pleased with the way we have treated him Boro are happy for Curtis to come here.
"The difficulty now for me is that Curtis won't be in Shrewsbury until later on Friday so the players haven't met him or trained with him so do I play him or wait until he's trained with us properly?"