Is it possible to apply for a Master's programme then leave current PhD? I'm a 2-year PhD student at a research institute in Asia, and now I'm thinking about applying for a Master's programme abroad (possibly in Australia or Europe), so is it possible for me to submit my application first, if I could be really lucky to receive an offer, then I leave my current PhD?

Here's my background. I earned my BS in optical information, and my final project was to investigate quantum machine learning, it really piqued my interest in machine learning, that's why I took my Master's programme on data analysis. Things went well at first, the research institute I'm in is part of a larger system, so the first year we were all gathered to finish our courses in a universty. In the second year, we were summoned back to respective institutes to finish our studies.

I was hoping that I could finally get to know more about scientific research, but it turned out that it was just the beginning of the nightmare. I was assigned to a team led by a certain PI, everyone on the team is this PI's subordinate, even my so-called supervisor. The PI is the kind of person that won't allow others to say "no" to him, and he initially asked me to investigate situation awareness, then switched the topic to object detection. At that time I didn't put much thought into it, so I applied to continue my study as PhD student, and stayed on the team.

To cut a long story short, I was then asked to work on multiple object tracking, remote sensing, spatial-temporal data mining, event detection in videos, graph-based data mining and information centric networking. That's 8 different fields in 2 years. I just can't stand it anymore, I've never recieved any proper guidance since I got back to the institute, all the PI wants is asking students on the team to write a report about certain fields so he can make better judgement when outsourcing the project. 

I'm still passionate about my research, I keep reading papers and conducting experiments on computer vision and deep learning, but haven't made much progress, I have no one to discuss my research idea with, as no one on this team really knows these things, the PI and supervisor really don't care about students' research since they can still make resonable profits by outsourcing projects, they just keeps distracting students with endless reports to write.

This is why I made up my mind to apply for a Master's programme abroad, I desperately yearn for better guidance, hopefully it can make me better prepared, so I can eventually do some real PhD.
is it possible for me to submit my application first, if I could be really lucky to receive an offer, then I leave my current PhD?


I don't see why not! It seems like this good be a good approach for you to pursue your research and career goals. You can go ahead and apply and try to put together the best application possible.