I want to generate sinewave by using Ad9833 and an amplifier on LT Spice IV but this Ic is not available,so how i can make this schematic to get sinwave? It would be great if anybody can help!
You can import other vendors' SPICE model files into LTSpice. If the other vendor (you mention an Analog Devices part number) provides a Spice model, you can add that to your LTSpice library and create your own custom symbol for it. Then you can add it to your simulation schematic.
Wurth Elektronics has a really nice hardbound book titled "The LTSpice Simulator", ISBN 978-3-89929-258-9. There are other online references for LTSpice as well.