Pembangkit Listrik Tenaga Uap (PLTU) Paiton unit 7 has a generating capacity of 615 MW. As a large-capacity power plant it certainly has a large generator capacity too. Generators in generating electrical energy over time the generator will experience a decrease in generator performance. In this study, discussing the performance of the generator 280T330 at the PLTU PT. POMI Paiton unit 7 by analyzing several generator performance parameters whether in accordance with generator design standards. The results of the study found that at the generator output there is active power, output voltage, output current, reactive power and apparent power. For the highest yield, each of them is 604.85 MW, 21.6299 KV, 16.5912 KA, 231.7503 MVAR, and 645.1330 MVA and the lowest results are 465.74 MW, 21.3461 KV, 12.1307 KA, 11.2169 MVAR, 474.5290 MVA. From the generator output, the performance of the generator is in a reliable state because the results are still in accordance with the generator design. The results of the power factor are the highest of 0.998 and the lowest is 0.9298. From the results of the power factor, the performance of the generator is reliable because the results are no more and no less than the design of the power factor of 0.85. The results at the highest frequency are 50.17 Hz and the lowest is 49.80 Hz, which means the generator performance is based on frequency in a reliable state because the results are in accordance with the tolerance limit of ± 5. The highest efficiency results are 98.87% and the lowest is 94.73%. Generator performance based on the efficiency that the generator is in a reliable state because the results are in accordance with the tolerance limit of ± 5%.