In view of the problems of the micro drill resistance instrument developed in the early stage, such as the direction of the drill drilling into the tree deviated from the straight line, the width of treerings cannot be obtained accurately, the mechanical structure and software algorithm of the micro drill resistance instrument were redesigned, the improvement measures of changing the drill shape and adding the drill support baffle were put forward, and the calculation method of the treerings’ width was given. The principle and the expression method of drill resistance of self-made micro drill resistance instrument was described. The number of tree-rings and the width of tree-rings of nine Pinus massoniana discs were tested by self-made micro drill resistance instrument, Resistograph 650-s and Lintab 6 respectively. The results measured by Lintab 6 were taken as the true value. The tree-rings recognition error rate and the measurement accuracy of tree-rings’ width of self-made micro drilling resistance instrument and Resistograph 650-s were calculated respectively. Most boundaries of tree-rings identified by the two micro drill resistance instruments corresponded to the late wood position of the treerings. The measurement accuracy of tree-rings width of self-made micro drill resistance instrument was 86.40%. The measurement accuracy of tree-rings width of Resistograph 650-s was 84.93%. And the average accuracy of the tree-rings width measured by the two instruments was as high as 85%, which showed that the micro drill resistance instrumentwas feasible to measure the number of tree-rings and the width of tree-rings. The error rate of tree-rings recognition of self-made micro drill resistance instrument was 12.7 percentage points lower than that of Resistograph 650-s, and the measurement accuracy of tree-rings width of self-made micro drill resistance instrument was 1.47 percentage points higher than that of Resistograph 650-s, which indicated that the mechanical structure design of self-made micro drill resistance instrument was reasonable and the tree-rings recognition method was feasible.