The temperature-dependent characteristics of an AlGaAs/InGaAs/GaAs pseudomorphic high electron mobility transistor (PHEMT) with an electroless plated (EP) deposition approach are studied and demonstrated. Based on the low temperature and low energy deposition, the EP deposition approach can form a better metal-semiconductor interface with the reduction in surface damage. Experimentally, the EP-based device shows a significantly improved dc performance. Good experimental results, including a high Schottky barrier height of 0.831 (0.759) eV, low ideality factor of 1.10 (1.32), high turn-on voltage of 0.75 (0.51) V, low reverse leakage current of 3.9 (161.4) mu A/mm, improved threshold voltage of -0.43 (-0.61) V, and high maximum transconductance of 225.8 (160.9) mS/mm, are obtained at 300 (500) K. Moreover, the EP approach also has the advantages of easy operation and low cost.