please clarify, do you want to ligate a PCR product and then digest it, or do you want to digest the PCR product and then ligate it?

i want to digest the PCR product and then ligate it

Sounds like trying to do it simultaneously is making your life more difficult than it needs to be.  You'd need a way to prevent the enzyme from cutting your ligated site.  We'd need to know more details about your situation, to see if that's even possible or how it might be done.   Why can't you do it sequentially? 

I agree with John - design your experiments as easy as possible!

However, since after ligation the sequence does no longer contain a restriction site for EcoRI or BSP119I also the one-step approach should work. But I would rather do the restriction digest and the ligation sequentially.

Hello

I agree with researchers PCR is very sensitive .

pleas , find these paper ( Enzymatic ligation assisted by nucleases: simultaneous ligation and digestion promote the ordered assembly of DNA ) by " Gregory J Cost " . Was describe method for the one-tube preparative-scale assembly of a specific DNA molecule, the enzymatic ligation assisted by nucleases (ELAN) technique .

Abstract of the paper :

This protocol describes a method for the one-tube preparative-scale assembly of a specific DNA molecule, the enzymatic ligation assisted by nucleases (ELAN) technique. DNA fragments in ligation reactions are capable of combining to produce numerous products. The ELAN method uses judicious choice of restriction enzyme sites coupled with simultaneous digestion and ligation reactions to create just one product, by converting off-pathway products back into substrate. The experimental parameters critical for a successful ELAN reaction are discussed, and the ordered, one-tube assembly of four DNA fragments in the presence of eight restriction enzymes is demonstrated. This technique will be useful to those performing gene construction, DNA computing, biophysics and even standard molecular cloning. Starting with reactant fragments, the protocol takes 4–16 h to produce nanogram to microgram yields, depending on the complexity of the reaction.

Hope help you . Good Luck