Cutting fluid occupies an important position in the metal processing. The performance and pollution problem brought to the environment of cutting fluid are paid attention to day by day. Proceed from the perspective of green design, using castor oil which has a good biodegradability, triethanolamine, boric acid and the sodium polyacrylate whose molecular weight is less than 2×104 as the main raw materials, a boron-containing water-based cutting fluid had been obtained. The performance of B-containing water-based cutting fluid are measured according to GB/T6144-1985 regulation which is the technical requirements of synthetic cutting fluid. And the biodegradability of mineral oil, castor oil, modified castor oil and B-containing water-based cutting fluid are measured by improved Storstroem Test (OECD301B). The test results show that the B-containing water-based cutting fluid has a good performance of physical and chemical. And the biodegradation rate of the cutting fluid is 87%, which indicates the cutting fluid has a good biodegradability.