Coriolis flowmeter measurement tube erosion wear is a very common phenomenon, the ac-curacy and service life of the flowmeter can be affected. In order to ensure the Coriolis mass flowmeter to work properly, the wear in the measuring tube must be checked regularly. At present, Coriolis flowmeter measuring tube wear detection are used offline test mode, Coriolis flowmeter can not be monitored in real time. The influence of wear on density measurement of Coriolis flowmeter is analyzed in this paper, an on-line detection method for pipeline wear of Coriolis flowmeter based on density change is put forward, and the simulation is carried out by ANSYS. The simulation results show that this method can effectively realize the on-line detection of pipeline dirt of single straight pipe Coriolis flowmeter, which has certain practical value.