The refraction effect of Water2 is not ideal enough

Thanks for your reply. According your advice, I test Refractor and Reflector class. The followed pictures are results.
Reflection result


Refraction result


The effect of Reflection is correct, but the effect of Refraction is incorrect. And I considered that the complexity of model may influence the effect. So I replaced the model with a simple box, and the effect is not ideal too. The edge of refractor are incorrect.