The 38-13 defeat to Italy in the opening match of their four-team European group section on Monday put a dent in Scotland's hopes of qualifying for next year's tournament in New Zealand.
Only the winners of the group, which also features Ireland, will qualify automatically with the runners-up progressing into a final qualifying round.
Head coach Bryan Easson has made two changes to his starting line-up to face a Spanish side who secured one of their greatest ever results in the opening round of fixtures after a dramatic late try sealed an 8-7 win over Ireland.
Louise McMillan comes into the second-row in place of Sarah Bonar, who is unavailable due to work commitments, while Rachel McLachlan steps into the back-row from the bench.
Easson said: “Our opening match of the tournament was a disappointment and not a true reflection of the hard work our players have put in over the past year.
“We will be put to the test against Spain, who we expect to be extremely motivated following their result against Ireland last weekend, but our players have responded well on-and-off the pitch this week and are determined to deliver a performance that keeps our qualification chances in sight.”
Leah Bartlett, Lana Skeldon and Christine Belisle once again join forces in the front-row, while Emma Wassell starts alongside McMillan in the second-row.
The match takes place Stadio Sergio Lanfranchi in Parma, kicking off at 5pm UK time, and will be shown live on BBC Alba.