In order to carry out the study of biological effect on high-voltage pulsed electric field with super-low-frequency, a numerical control high-voltage pulsed electric field treatment system was designed. This system can generate high-voltage pulse with super-low-frequency, wide pulse width and steep edge. The amplitude of pulse voltage is adjustable from 15 to 20 kV, the pulse frequency is adjustable from 0.1 to 50.0 Hz, and the pulse width is adjustable from 10 to 5000 milliseconds. This system has advantages of simple structure, low cost and high dependability. Using the pulsed electric field with 240 kV/m, 10.0 Hz and 50 milliseconds pulse width to treat aged cotton seeds with two kind of electrode, the results showed that: (1) The four germination indexes of cotton after pulsed electric field treatment by arc-shaped prick electrode array showed a trend of increasing. Under the 40 seconds treatment condition, the germination potential increased by 27.3%, the germination rate increased by 45.5%, the germination index increased by 42.9%, the vigor index increased by 71.1%, and the four indexes had the most significant difference (P