This study systematically investigates the effects of different anode work function metals (Ti/Au and Ni/Au) on the transport and temperature characteristics of β-Ga2O3 based Schottky barrier diodes (SBD), junction barrier Schottky diodes (JBSD), and P-N diodes (PND), utilizing Sentaurus TCAD simulation software for mechanistic analysis. From the perspective of transport characteristics, it is observed that the SBD exhibits a lower turn-on voltage and a higher current density. Notably, the turn-on voltage (Von) of the Ti/Au anode SBD is merely 0.2 V, marking the lowest recorded value in the existing literature. Furthermore, our study reveals that the turn-on voltages of the two types of PNDs are nearly identical, confirming that the contact between the anode metals and NiOx is ohmic contact, and the contact between Ni/Au and NiOx exhibits a lower contact resistance. The Von, current density, and variation rate of the JBSD lie between those of the SBD and PND. In terms of temperature characteristics, all diodes can work at 200 °C, with both current density and Von showing a decreasing trend as the temperature increases. Among them, the PND with a Ni/Au anode exhibits the best thermal stability, with reductions in Von and current density of 8.20% and 25.31%, respectively, while the SBD with a Ti/Au anode shows the poorest performance, with reductions of 98.56% and 30.97%. Finally, the reverse breakdown (BV) characteristics of all six devices are tested. The average BV for the PND with Ti/Au and Ni/Au anodes reach 1575 V and 1550 V, respectively. Moreover, although the Von of the JBSD decreases to 0.24 V, its average BV is approximately 220 V. This study demonstrates that β-Ga2O3 based power diodes continue to exhibit excellent characteristics and application prospects in terms of low turn-on voltage.