The invention provides a novel high-resistance electrothermal alloy Cr20Ni80Al, and further provides a preparation process of the novel high-resistance electrothermal alloy Cr20Ni80Al. The constituentelements of the novel high-resistance electrothermal alloy Cr20Ni80Al include, by weight percentage, C<=0.03%, Si:1.40-1.60, Mn<=0.50%, P<=0.020%, S<=0.015%, Cr:20.5-21.50%, Ti<=0.10%, Al:3.0-3.7%, Fe<=1.00%, Zr<=0.2%, and the balance of Ni and unavoidable impurities. Compared with prior electrothermal alloys, the novel high-resistance electrothermal alloy Cr20Ni80Al has the excellent performances of being higher in resistivity, longer in service life, very good in processing performance, excellent in oxidation resistance, small in thermal expansion coefficient, good in high temperature strength, etc., and is of great economic significance to improving production efficiency, ensuring product quality and reducing production costs.