In order to investigate the total-dose irradiation effects of Altera static random access memory (SRAM) -based FPGA (field programmable gate array), the irradiation response of basic cell of FPGA, i. e. the CMOS, is studied, and the relationship of the output waveform as a function of total dose has been obtained. It indicates that the output waveforms become aberrated and the peak-peak value turns to about 1/10 of the initial value as the total dose increased, resulting from the degradation of leakage current both from field oxygen and the structure; but there are relatively high and low levels left in the output waveforms. Meanwhile, the high level can't keep the already existing state and changes to the low level, and the conversion speed it; accelerated with the increase of the total dose. The low level becomes larger than the initial value. As the gate-oxygen is quite thin, the rise time, fall time, and delay of the output waveforms change little with the total dose.