The invention relates to cutting fluid, in particular to semi-synthetic metal cutting fluid. The semi-synthetic metal cutting fluid is prepared by methyl levulinate, (R)-(+)-2,4-dyhydroxy-N-(3-hydroxypropyl)-3,3-dimethylbutyramide, 2-oxo-1,5-disoidum glutarate dihydrate, 4-piperidone-3-carboxylate hydrochloride and trimethylsilylketene. The semi-synthetic metal cutting fluid has good cooling, anticorrosion, antirust and lubricating performance, service life of a knife can be prolonged effectively, and excellent machining accuracy can be realized; the semi-synthetic metal cutting fluid can play a role in safely and reliably protecting and inhibiting corrosion of nonferrous metal like aluminum and steel and ferrous metal, so that time and cost for subsequent treatment can be omitted; the semi-synthetic metal cutting fluid is suitable for being widely popularized and applied in the field of the cutting fluid.