The utility model discloses an oil sample anti -pollution device, including sample pipe fitting, dustproof cap, sealing washer and shield, sample pipe fitting upper portion level has the fluid entry,and the middle part is crooked, and the lower part is vertical to have oil liquid outlet, has the external screw thread on its lower part outer wall, the sealing washer sets firmly on the sample pipefitting outer wall of external screw thread top, the dustproof cap sets firmly on sealing washer top sample pipe fitting outer wall, its cap orad down and cap mouth department internal diameter be greater than sample pipe fitting external diameter, shield upper end opening, the lower extreme seals, and its internal diameter and sample pipe fitting external diameter equal that its external diameteris lighter than dustproof cap cap mouth department internal diameter, and its upper portion inboard is equipped with the internal thread, should be greater than outer thread length by interior threadlength, the shield passes through internal thread and sample pipe fitting detachable connection of external screw thread to can go on reliably sealedly with the sealing washer. The utility model discloses simple structure, simple to operate, the operation is swift and be suitable for, can prevent effectively in the oil sample work that pollution sources such as solid particle and dust get into the sample, and the practicality is strong.