In a 2012 interview with the artist, Ka Xiaoxi, at the beginning of his commercial career, he explains:
I was inspired by Terry Richardson at the beginning. I loved his photos so much at the time. Now, I like others such as Helmut Newton, Jurgen Teller, Ryan McGinley, Hasisi Park, Tim Barber, etc. My style's very casual now, with some certain "Ka" style that's developing. I love to use flash and shoot people. that's all.
Terry Richardson is an American fashion and portrait photographer — and alleged sex offender (see e.g. this New York Magazine article and other articles going back to at least 2010). But, focusing purely on the work (and, hey, even with all that creepiness aside, here's Barack Obama and Oprah), you can see some stylistic similarity, particularly in the use of direct flash and an overall high-key exposure (yet without the raised black points which are trendy these days).
Ka Xiaoxi's photographs, though, have a lot more context — in both the article about rich Chinese youth and the Nike-sponsored series about China's street basketball culture, the background and environment is important (rather than some makeshift celeb-studio white background as in many Richardson photographs). They feel very loosely composed, without much deliberation (although in actuality I think the setup is likely to be a little more mindful than it appears, even if also done quickly).
Anyway, as to a name: I think overall Ka Xiaoxi's work falls under the "snapshot aesthetic", characterized by use of apparently-naive techniques and often made with consumer-focused gear (like instant cameras) — or made to follow that look even if actually created differently.
There's an interesting read on this at the University of Rochester's "InVisible Culture" journal — Snapshot Aesthetics and the Strategic Imagination, which I think is particularly relevant given Ka Xiaoxi's work as a commercial photographer, (and the part of the question above which asks why this particular style is "captivating"). To quote in part from that article:
Snapshot-like imagery emerged as a powerful vehicle for showing consumers “in action” with products or using services. A key aspect of the snapshot style is an appearance of authenticity; snapshot-like images often appear beyond the artificially constructed world of typical corporate communication. This visual quality can be harnessed to promote organizations as authentic, to invoke the average consumer as a credible product endorser, or to demonstrate how the brand might fit in with the regular consumer’s or employee’s lifestyle. I place snapshot aesthetics within a genealogy of “everyday” depictions in visual culture, in particular twentieth-century street photographers such as Robert Frank, Lee Friedlander, and Garry Winogrand. I discuss a small set of contemporary uses of snapshot aesthetics in marketing communication, including the work of photographer Terry Richardson.
As for the actual technique used: I don't think it's particularly fancy — bare flash on or near the camera (possibly even ring flash), and exposure adjusted to the higher register (if you look at the histogram for most of these photos, a preponderance of tones are in the upper 20%, but there's a lower, even distribution throughout). There may be some post-processing, but you could do this by tuning the JPEG settings of most modern mid-range mirrorless or DSLR cameras. In fact, in keeping with the notes about snapshot aesthetic above, the relatively high color saturation and sharpening are similar to the default output of many lower-end models.
