Preheat the oven to 350°F (175°C).
Combine crushed pretzels, melted butter, and granulated sugar in a mixing bowl.
Press the pretzel mixture into the bottom of a 9x13 inch baking dish.
Bake for 10 minutes, then allow cooling completely.
In a mixing bowl, beat the softened cream cheese with powdered sugar until smooth.
Fold in the whipped topping gently to the cream cheese mixture.
Spread the cream cheese mixture over the cooled pretzel crust.
In a separate bowl, dissolve strawberry gelatin in boiling water.
Let the gelatin mixture cool slightly before adding sliced strawberries.
Pour the gelatin over the cream cheese layer and refrigerate for at least 4 hours to set.