hello
how many km can s600 v12 engine can do?

Do you mean km/hr?

Answer could be 200,000 or 200.

I mean: if I buy an used s600 with 150.000 km, how many km can I do before having to change the engine?

I don't think that anyone but a well-versed mechanic who takes a look at that car's engine can tell you that. If you're interested in the car, and concerned about its condition, agree with Buyer for you to take it into a knowledgeable mechanic who can tell you what kind of shape it's in -- and probably also how well those motors do in general over time.... IMO 150K km is not that much mileage for a high-end european car -- but then I don't know about that car and that motor specifically.
Anytime I buy used I have my or a mechanic check it out....basic.

what do you mean?
150k km well done (1000 - 2000 rpm) , +/- how many km can do yet?

You have two diesels? Those things should run a long time before they're kaput. In my experience you should get the same type of usage out of a well-engineered and constructed gasoline motor - 225,000 km to 300,000 km before rebuild, 500,000 km or more in total.
If someone abuses the heck out of a motor? Whole different ballgame. If the prior owner(s) treated it well? Even better, it will run forever if you treat it well too.
That's what I'm trying to say. Today's motors, especially the highly-engineered and well-made ones, can last a very long time. Once again, I do not have specific knowledge about the motor in the car you are considering -- but a mechanic who services those motors should.....

150 000km arent anything for S600. It can do above 500 000km and still be in a good condition. Even my friends 00 Grand Cherokee has 152 000km on the clock and it still handles like new. Different question would be if you live in some eastern countries like Russia or Ukraine, that would be too bad for such car.
But in your case 150k are nothing to S600.

so:
s600 should do 500.000 km
and my s320 cdi?
and my c220 cdi?

I read messages on web of people that had to change engine at 50,000 - 60,000 km for 20,000 euros.