Taking the connecting rod small end bearing of non-road high pressure common rail diesel engine as the research object, the eddy current method-based axial trajectory testing system was built, and the data acquisition software was developed. The axial trajectory testing and analysis of connecting rod small end bearing were carried out under idle condition. The results show that the axial trajectory testing based on eddy current method realizes the synchronous acquisition of eddy current and crankshaft angle signal. Under the idle condition, the oil film thickness of bearing fluctuates periodically in the range of 0-20 μm, the peak value appears in the intake and exhaust stages, and the minimum oil film thickness is 0.88 μm and appears at 21° after the in-cylinder maximum combustion pressure point. The motion of bearing axial trajectory is primarily characterized by vertical oscillation, and the main load-bearing zones of bearing distribute in the circumferential intervals of 60°-90° and 270°-300°.