There ought to be a historical link to why there isn't a Chinese victory day. Chinese culture was never inherently celebrative of some massive efforts/triumph against some dominating force or just to celebrate the fame and glory of some momentous occasion. I mean there should be a national holiday for Yu the Great because he battled floods? but there isn't one. What about when the first Zheng He voyage made the trip back shouldn't that be a moment worth celebrating? after all there is a Columbus day. At most the achievements are codified in some 24 histories to be read and possibly discussed but not really celebrated with a festival which marks the anniversary of the occasion.
In Republican China era, there were half a dozen "national humiliation" days, including the day Japan successfully pressed the 21 Demands onto China in 1916 and the day Japan attacked Jinan the provincial capital of Shandong in 1928. R.O.C. does have the victory day, which was called "抗日战争胜利纪念日", the day Japan signed the official surrender paper on Missouri.
Communist China, to avert the R.O.C.'s feats, declared August 15, the day Japanese emperor announced the surrender, as the victory day. However, some vase party, termed "Sept 3rd Society" somehow made Zhou Enlai announce the Sept 3rd as the victory day for the P.R. of China. But nothing in the PRC stuck, and politics overwhelmed this announcement, and even though this date still exists on paper, it is not a national holiday, but more like a festival like the Mid-Autumn Day.