Green green guava leaves (Syzygium javanicum Miq.) has been known contains a lot of phytochemical compounds that is useful for human health as antioxidant such as phenolic, flavonoid, and tannins but unfortunately this function still not exploited too well. The purpose of this research was aimed to study the effect of temperature and steeping time on the antioxidant activity of “black tea” green guava leaves and compare the antioxidant activity of “black tea” green guava leaves with fresh green guava leaves, dry green guava leaves, and decoction of fresh green guava leaves to get the best treatment. “Black tea” green guava leaves were brewed with different temperatures: 70, 85, and 100°C and steeping time: 5, 15, 25, and 35 minutes and then the optimal results were used to compare with steeping of fresh green guava leaves, dry green guava leaves, and decoction of fresh green guava leaves. “Black tea” green guava leaves with 35 minutes steeping time at 100°C (361,06 ± 12,72 ppm) had the highest antioxidant activity among the other treatments and also had the highest total phenolic content (725,37±18,29 mg GAE/ L sample), flavonoid content (85,27±2,58 mg QE/ L sample), and condensed tannins content (86,46±1,82 mg CE/ L sample). Furthermore, based on the research that has been done, “black tea” green guava leaves had the highest antioxidant activity, total phenolic content, flavonoid content, and condensed tannins content compared with fresh and dried green guava leaves steeping and decoction of fresh green guava leaves