What to do if I only want to study master not PHD with a professor I decided to study math after graduating from business department. I entered a 2-year taught program in the same university in Asia and used the time to take all the necessary courses. In the first year, I have studied elementary real analysis, complex analysis, abstract algebra and topology. This is the first term of my second year, I took differential geometry, Fourier analysis, graduate real analysis and functional analysis. My grade is OK and currently I am applying for a research program. My final goal is to go to a top program in US to study my PHD. Since I know it is very competitive, this year I decided to apply a research master only and apply PHD after I gained two-year research experience.

There is a tenured professor in my university whose research interest is nonlinear PDE focusing on fluid dynamics. I am very interested on his research topic and I have made an appointment with him to explore the possibility to do research under his supervision.  However, after chatting with one of his student today, I was told the professor usually only accepting student who is willing to continue studying PHD with him. I understand the reason. Since it's a pure math subject, in the first two year, student can only take the basic course, read the basic materials. It's almost impossible for a student to produce any good results after the master. He is very famous in the area so he has a lot of students to select. He don't want to waste the money and time to train a student for others. 

On the other hand, I don't think my university is good enough and it's my dream to work and study with the best students in a top program. Since I will meet the professor in a few days, I want to make some preparation so that I can convince his to support me. I will finish all the necessary graduate courses after this year, which means it may safe me some time so that I can focus on research instead of coursework in the research program. But I still think it's impossible for me to produce the same result as a PHD student in 2 years. But since I am really interested in the area, I still want to have a try and talk with him. Currently I am planning to tell him the truth about my plan. Is there anything I can do to improve the chance of being admitted?
I would focus most of the meeting on the professor's research, and use that time to show that you would be able to jump into research right away.  Probably the best way to do that is to


Read the professor's papers beforehand and display a sincere interest in his work.
Have an elevator pitch prepared for each of your previous projects so you can talk about them intelligently and with enthusiasm.


If the meeting goes well he should start discussing potential projects with you, and you should be actively engaged in this discussion, and ask intelligent questions.

Near the end of the meeting, inform him of your plan to do a PhD elsewhere.  It's better to be rejected by this guy upfront than to be accepted under false pretenses.  In order to go to a strong university you will need his letter of reference, and he might write you a weak letter if you deceive him.  (If he's really a jerk he might write you a weak letter specifically so you have to stay with him.)

But it's important to discuss this issue after he already wants you, and is on the verge of making you an offer.  Otherwise he has no reason to even consider you.

(If he specifically asks about your future plans, you should be honest and unapologetic.  To many professors, being ambitious is a good thing, and shows you are higher quality than the students who come in wanting to stay.)