In order to study the affected signal that caused by movement velocity of oil samples when content of iron particles was detected, the method of inductance is used. MicrochannelsInductive detection chip was designed and manufactured, and detection system was established. Through experiments, the induction signals at different movement velocities were detected, which were then compared and analyzed. The results show that the detected signal is reduced linearly with the increasing of movement velocity of oil samples passing microfluidic chips, in the hydraulic oils with same amount of content of iron particles. The study has important significance of reference for improving accurate detection of content of iron particles in hydraulic oil. 