The definition of a cold filter point is: when the sample is cooled under specified conditions and under negative pressure of 200mm water column, the high temperature occurs when the sample cannot pass through the filter (363 mesh) or when 20ml of the sample passes through the filter for more than 60 seconds or when the sample cannot flow back to the test cup. The cold filter point can better reflect the actual low-temperature performance of diesel than the cloud point and freezing point, and is close to the actual low-temperature performance of diesel.