Direct measurement of the height of the rock surface reduction is an effective method to estimate the erosion rate of exposed rocks. In this study, we introduce the composition and principle of a high precision portable vernier helical micrometer measuring device. T- shaped bracket and base sleeve were added to the base of the original device and the improved device has been used for field measurements in the Tangshan area. 98 points were measured, and a single point was repeated 5~15 times yielding a total of 1005 sets of data. There are 74 points with maximum differences of less than 0. 1 mm accounting for 75. 5% of allmeasure dpoints, 87 points with an average deviation less than 0. 1 mm accounting for 88. 8% of all measured points, 86 points with standard deviation of less than 0. 1 mm accounting for 88. 8% of all measured points. Based on our research, we believe that direct measurement of surface rock erosion rate with portable high precision vernier helical micrometer is feasible in some high erosion areas. The measuring accuracy can be further increased by improving the device or increasing the number of measuring points.