The invention discloses a method for machining the inner layer of a rhombus alloy pot and belongs to the technical field of machining. The method comprises the following steps that step1, a rhombus pattern is pressed on an alloy iron plate; step 2, the surface of the pattern is electroplated with a mixture of ferric oxide and stannic oxide; step 3, through machining of a numerical control milling machine, parameters are input and the surface of the plate is milled smoothly; step 4, a machined piece is placed in a polishing machine for polishing so that a rhombus alloy plate can be formed; step 5, the rhombus alloy plate is installed on the inner layer of the alloy pot by means of stamping. The method has the advantages that food cannot adhere to the inner layer of the pot and generation of cooking fumes is avoided in the process of cooking.