An integrated structure of CMOS devices includes: a semiconductor layer, insulation regions, a first high voltage P-type well and a second high voltage P-type well, a first high voltage N-type well and a second high voltage N-type well, a first low voltage P-type well and a second low voltage P-type well, a first low voltage N-type well and a second low voltage N-type well, and eight gates. A CMOS device having an ultra high threshold voltage is formed in ultra high threshold device region; a CMOS device having a high threshold voltage is formed in high threshold device region; a CMOS device having a middle threshold voltage is formed in the middle threshold device region; and a CMOS device having a low threshold voltage is formed in the low threshold device region.