Abstract: Demands of various engineering on measuring accuracy are higher and higher, The first program in surveying and mapping is measuring instrumental height, the precision of measuring instrumental height will determine the overall precision of the measurement field. This paper introduces the common methods of measuring instrumental height, and makes local changes to tripod and matches a new design of a ruler. In the end, it puts forward a new method of measuring instrumental height, which is simple in operation and have good feasibility. In addition, it can improve the accuracy of measuring instrumental height and gain high popularity. In this paper, the idea provides a new reference for measuring instrumental height in measurement field and provides a new idea for improve instrument.

Key words: measuring instrumental height, the method of steel rule measure distance, corner bracket, active knob, precision analysis