Racial ingroup favoritism in empathic brain activity has been widely observed and is associated with biased behavior toward same-race and other-race individuals. We investigated whether racial outgroup favoritism in neural responses to others’ pain — an objective measure of empathy — may emerge during sociocultural interactions in a new social environment. We recorded magnetoencephalography to pain and neutral expressions of Asian and White faces from White students who had stayed in China for 6–36 weeks (Experimental group) or 2–4 weeks (Control group). The experimental group showed better neural decoding of and greater insular/sensorimotor responses to pain vs. neutral expressions of Asian compared to White faces. By contrast, the control group showed better neural decoding of pain vs. neutral expressions of White than Asian faces. In addition, participants of the experimental group who had stayed longer in China showed greater sensorimotor responses to pain (vs. neutral) expressions of Asian faces but weaker sensorimotor responses to pain (vs. neutral) expressions of White faces. Our findings revealed emerging racial outgroup favoritism in brain activities associated with sensorimotor resonance and affective sharing of others' pain during sociocultural interactions.