During electrical power generation by permanent magnet linear generators (PMLGs) from the oceanic wave, there is a temperature rise in the translator and stator core. This phenomenon badly affects the performance of permanent magnets (PMs) causing demagnetization which further degrades the generation of electrical power from almost all the PMLGs. This paper investigates the effect of temperature rise on the conventional neodymium iron boron (NdFeB) PMs and proposes a PMLG with recently developed N28EH NdFeB PM. The temperature effect for both the existing and high grade neodymium iron boron (NdFeB) PM are analyzed. The voltage, current, flux linkage, and power curves of the proposed PMLG are shown for comparison. Simulation results show that, for the same operating temperature, the generation of electrical power of the PMLG with N28EH NdFeB PM is more compared than that the existing one because of preventing demagnetization.