Soak china grass in water for 10 mins. Then heat it and cook till china grass is melted.
Now take jelly packet in a bowl, add 1 cup hot water and mix well. Pour it into a tray and leave to set in freezer for 30 mins. Now cut it into cubes. Transfer to a tray.
Now heat milk in a sauce pan, add condensed milk and bring it to a boil.
Add china grass mix and whisk well.
Pour this over the tray and leave to set in fridge.
Slice and serve.