In recent years, China's export trade to Africa has made rapid progress. By 2017, China had become Africa's largest importer for six consecutive years. Both countries have great trade potentialities. This paper chooses the trade data of 27 representative countries in Africa from 2001 to 2017 and uses stochastic frontier gravity model to study the trade efficiency and trade potential of China's exports to Africa. The results display that the trade efficiency of 27 African countries has a slow upward trend, but the overall efficiency is low and China's export trade potential to Africa has considerable room to improve. According to the factors which affect trade efficiency between China and 27 African countries, the population of importing countries and the per capita GDP of exporting countries can promote trade, but the per capita income gap and financial crisis are the factors will hinder trade. In the future, through setting about China-Africa institutional cooperation, infrastructure assistance to Africa, China-Africa trade investment environment and brand quality, China will improve trade efficiency and release trade potential further.