Render have problem is have lot of block

HI  I am kiki, i am from Taiwan desinger girl , i use the  dimension tool ,when i  render the design psd or

png  is have lot of blockit  is may me confused , Have any good guy can help me why happen?

!@ thank you very much。

And  I want to present plastic transparency, is like as PVC Box package

how to operate and set? it is  Can't combine transparency with background