In this article, I would like to consider how Protestants was formed in Indonesia after the Japanese occupation in 1942, how it has grown after the independence, and through what process the Islamic conflict has intensified. In addition, I would like to examine the Pentecostal movement, which is vitalizing the growth of Christianity in Indonesia. Japan’s occupation of Indonesia was only three years, but Indonesian Protestant leadership was transferred to the locals and foreign missionaries who had played an absolute role began to be pushed around. And the Protestant Indonesian ethnic group began to respond to the request of a new era of church unity.<BR> Christianity was able to reveal the colors of Christianity in a situation where, after independence, various races had to be embraced, where religion had not yet been fully established, and even in areas where certain religions existed. In addition, the Indonesian government ordered all citizens to choose one of the six religions and list their religion in their IDs in order to break the communist bonds. So, after 1945, there was a massive conversion to Christianity in Indonesia.<BR> However, this trend of growth marks a new phase in the time of President Suharto. By decree No. 70, since 1978, officials from Indonesia have been unable to missionary to Muslims and other religious groups. Muslims continued to increase the Christian population due to illegal missionary activity that violated the law, and the constant conversion to Christianity was accepted as a threat to the Muslim community.<BR> The reason for paying attention to the Pentecostal Church is that the Pentecostal movement plays an important role in growing Christianity in a serious conflict with Islam through the old and new order. After President Soekarno’s resignation, Western evangelicals and Pentecostals focused on reviving Christianity in Indonesia. Consequently, the Pentecostal Church in Indonesia has grown the third since the main Protestant denominations and Roman Catholics since 1970.