The invention is a component and preparation method of nickel nano-powder material with high Cr content, belonging to metal material filed. The invention is particularly suitable to be used for defending and repairing the four tubes of the coal burning boiler which are damaged by high temperature corrosion and abrasion. The weight percentage of the components of the powder material is as follow: 50 to 52 percent of nickel, 44 to 46 percent of chromium and 1 to 2 percent of carbon. The method comprises the steps as follow: prepare the primary powder through vacuum melting and atomization powder producing technique; and process the powder for 16 to 20 hours through ball milling technique under the protection of liquid nitrogen to produce powder, and the grain size of the powder is nanometer level. The powder material has excellent fluidity and thermal stability. The invention has the advantages of improving the quality and the level of the defending coat, increasing the comprehensive service performance of the coat, further increasing the anti high temperature corrosion and abrasion capability of the four tubes of the coal burning boiler. The organization density, the micro-penetration hardness, the anti sulfuration corrosion capability and the anti oxidation capability under 500 to 650 DEG C of the nano-structure coat which is prepared by the powder material through supersonic speed flame spray coating are all better than that of the micron meter structure coat which has the same components and is prepared by the same method.