Abstract: To solve the problem that the spring tea is seriously damaged by Apolygus lucorum while we lack related control index, the field counting method of nymphs was studied according to the damage characteristics of A. lucorum nymphs. We conducted a field experiment to measure the economic loss rate of fresh tea leaves under different population densities of A. lucorum. Combining the economic loss rate of fresh tea leaves with the cost of control and fresh tea leaves benefit, the control index of A. lucorum could be determined with population density as a measure in Rizhao tea area. The results showed that: the activity range of A. lucorum in tea bushes was affected by the density of fresh leaves; the feeding behavior of A. lucorum usually occurred in a small range if the density of fresh leaves was relatively high; on the contrary, they would feed in a slightly large range; but no matter what kind of tea garden it was, the feeding activities of A. lucorum was within a circle whose horizontal diameter of the tea bushes was no more than 70 cm; the control index of A. lucorum should be 0.99 pests/1000 tips in the area to pick single bud, 1.08 pests/1000 tips in the area to pick one leaf and one bud and 1.48 pests/1000 tips in the area of picking one leaf and two buds. The control index with the population density of A. lucorum as a measure has high accuracy. It provides a scientific basis for the tea gardens whose control expenses and fresh tea leaves income are similar with Rizhao’s. However, A. lucorum nymphs are generally in an aggregate distribution, always live in seclusion and newly hatched nymphs are too small to be found easily, we should take multiple observation counting methods to determine the population density.