Digital technologies have brought about a significant shift in the way people from different social groups participate in politics through increased information openness. However, the effects of information openness on the equality of participation remains controversial. In this paper, we argue that in developing countries, information openness empowers disadvantaged groups by reducing the cost of public information access, providing opportunities for social learning, and disseminating scarce political knowledge, ultimately bridging the participation gap. To test our argument, we conducted two complementary studies. The first study examined the impact of information openness on both online and offline participation using big data generated by the Baidu search engine and national surveys. The second study explored the effects of an exogenous information openness shock on the online participation. We find that information openness reduces participation gap, which contribute to the ongoing debate on the impact of information technology on political equality.