Competing in the W35 age group at the event in London, the West Linton athlete won the 200m in 26 seconds, finishing ahead of fellow GB internationals Krystle Balogun and Roisin McBride.
Returning to race in the 60m on the Sunday, Downie posted the fastest heat time of 7.97 seconds and got a brilliant start in the final to clinch gold in a faster time of 7.92 seconds.
She is now first in the UK for W35 rankings for both the 60m and 200m events, and sixth overall in the Scottish senior rankings for 200m.
Downie said: “It was my first time competing at these championships and I’m delighted to come away with two gold medals. This sets me up well ahead of the European Indoor Masters Championships in Torun, Poland in four weeks’ time.”