mm integrated flip chip ring mixer circuit is designed and simulated with HP ADS software. The simulated three ports isolation is nicer when RF is 35.1GHz and local frequency is 35GHz. Simulated the best LO power is 6～15dBm with computer, conversion loss is less than 5dB. 8mm integrated flip chip ring mixer with chip size 3×3.75μm 2 is fabricated. Measured results are almost consistent with simulated results.