Preheat oven to 375°F.
Combine crushed pretzels, sugar and butter in a bowl and press into the bottom of a 9x13 pan. Bake 10 minutes and cool completely.
In a medium bowl, mix cream cheese and sugar with a hand mixer on medium until fluffy. Gently fold in Cool Whip. Spread mixture evenly over the cooled crust and refrigerate at least 1 hour.
Large mixing bowl combine Jell-O and boiling until jello is dissolved. Allow mixture to sit at room temperature until completely cooled.
Place sliced strawberries over the cream cheese mixture. Pour cooled Jell-O overtop.
Refrigerate until firmly set at least 4-6 hours or overnight.