The natural mineral of polyhalite, which consists of potassium, sulphur, magnesium, and calcium, has the potential to be to supply various essential nutrients to complete the plant’s nutrient requirement, such as sweet corn. The aim of this study to determine the effect of multiple doses of K-Ca-Mg-S fertilizer on sweet corn plants. This research was conducted at Medan City, North Sumatra, with a height of ± 25 meters above sea level from March to May 2023. This study used a Non-Factorial Randomized Block Design with 5 replications and 5 treatments consisting of the dose of fertilizer, namely 0; 2.14, 4.28, 6.42, and 8.57 g/plant. The results of the study showed that several doses of K-Ca-Mg-S compound fertilizer were able to accelerate the male flowering age, which was 53.8 days after planting (dap), the female flowering age was 57.4 dap, and was able to increase the weight of husked cobs, namely 157.758 kg, and seed sugar content of 15.6 % Brix, but did not increase the harvest index.