Sister Yun's. By inquiring about the plot introduction of the novel Wang Xiaoer, it shows that in the ending of Wang Xiaoer, Wang Xiaoer didn't see Xiangxiang Liu at last, but stayed at Sister Yun's house for one night, so the little boy in the ending of Wang Xiaoer belongs to Sister Yun. Wang Xiaoer, an urban novel written by Wu Shi, was deeply loved by book fans as soon as it was published.