I have seen lots of UI designer nowadays including this kind of illustration i want to know the name of this style so that i can also learn and try this in my designs.
I bet you will not find any established name for the distorted perspective and dimensions of the human character in your image. And if someone had given a name for it, it's useless until you had built your own between-the-ears model what it has and how to draw everything.
So: Find some good works and try to copy them (for yourself only!). Decide what are the essentials. Then try to apply the findings to your own characters.
You will succeed if you are able to step up from copying.
BTW company named Tubik Studio seems to use plenty of this style human characters. Maybe their designer - probably Yaroslava Yatsuba - gives some hints if you ask.
ADD: User Danielillo wrote in his comment that Tubik Studio has given a generous explanation and they call it Flat Design.