Cake tea, a traditional beverage of China, has excellent health benefits. Our study investigated the phytochemical profiles, antioxidant, and antiproliferative activities of cake tea leaves, which were obtained from the same cultivar and processed at different intervals. The effects of bioactive compounds and antioxidant activities of 4 cake tea varieties on a human lung cancer cell line (A549 cells) were systematically examined. The content of total polyphenol, an active ingredient of tea, was significantly higher in green cake teas (14.0% ± 0.4a) than their black (4.8 ± 0.3c), yellow (10.0 ± 0.6b), and white (8.8 ± 0.5b) counterparts. Likewise, the content of total free amino acids in green cake tea (3.6% ± 0.5a) was significantly higher than the other tea varieties. Our results indicated that the extent of fermentation of tea leaves could decrease the antioxidant activities of cake tea leaves. Furthermore, the white tea cake variety demonstrated the maximum antiproliferative activity on A549 cells as opposed to other types of cake tea leaves. Such an observation allows future researchers to narrow down their focus on using specific cake tea types (sourced from the same cultivar) that provide the maximum health benefits.