A conventional tri-layer resist structure which consists of PMMA A4/PMMA-MMA/PMMA A2 is adopted to pattern the 210 nm T-gate resist profile in a single lithographic step and a single development step,in order to fabricate the T-shaped gate InAlAs/InGaAs metamorphic High Electron Mobility Transistors(mHEMTs) on a GaAs substrate. The DC and microwave performance of the device are characterized on wafer by an Agilent B1500 semiconductor parameter analyzer and an Agilent 360 B Vector Network Analyzer under room temperature,respectively. The mHEMT device shows the DC output characteristics having an extrinsic maximum transconductance gm:max of 195 mS/mm and the full channel current of 160 mA/mm. The cut-off frequency fT and the maximum oscillation frequency fmax for the mHEMT device with gate width of 50 μm are 46 GHz and 115 GHz,respectively. Meanwhile,work has also been carried out to determine the quality of the Ti/Pt/Au Schottky contact to InAlAs with remarkably small gate leakage current in the orderof 1×10-8 A/μm,which is extremely useful for the reduction of shot noise and the LNA applications.