The ribbon was cut by Wakefield Council leader Denise Jeffery with Claire Worton and Jenny Layfield from the musuem.
It will be open to the public from July 21.
Georgia Hill has been looking after the NCM’s three pit ponies – Eric, Ernie and Bud – and Clydesdale horse – Finn.
She said: “The last year has been alright but we miss the public, it’s been strange, very strange. The ponies didn’t really care, they’ve just adjusted as we’ve adjusted.
“Finn is the biggest horse you’ve ever met but he’s a big softy and loves cuddles.
“Eric and Ernie are grumpy old men and Bud’s a wind up merchant. He’s the youngest and wants to play but the others just want to be alone.”