In the present study we report the effect of A-site substitution by Potassium on the structural, magnetic and magnetocaloric properties in Pr0.8Na0.2-xKxMnO3 (0≤x≤0.15) samples synthesized using the solid state reaction at high temperatures. The Rietveld refinement of the X-ray powder diffraction shows that all our samples crystallize in the orthorhombic symmetry with Pbnm space group. The surface morphology of these samples was carried out using scanning electron microscopy (SEM). Magnetization measurements versus temperature in a magnetic applied field of 0.05T indicate that K doping leads to a paramagnetic-ferromagnetic transition with a Curie temperature TC increasing from 117 K for x = 0.05 to 132 K for x = 0.15.The maximum of the magnetic entropy change View the MathML source under a magnetic field of 5T is found to be 3.20, 3.44, 3.32, and 3.30 Jkg-1K-1 for x = 0, 0.05, 0.1 and 0.15, respectively. Large relative cooling power (RCP) value of 355.6 Jkg-1 is obtained for Pr0.8Na0.2MnO3 compound, at a field change of 5T. This relatively large value associated to a Curie temperature of 90 K make the present compound a promising candidate for magnetic refrigeration at low temperatures.