To reasonably conserve and utilize natural enemies for comprehensive control of pests in lawns, a t-test was employed to compare population differences of main pests and their natural enemies in Festuca arundinace and Ophiopogon japonicus. The results showed that the t value of the main pests Seapsipesus asperus, Chaotocnema ingonua, Sitobion avenae and Geocoris pallidipennis were 0.7938, 1.8587, 0.9302 and 4.8237, respectively. An extremely significant and significant difference（t_0.10=1.72）in the number of Geocoris pallidipennis and Chaotocnema ingonua between two lawns was observed, respectively, but no significant difference was found in the number of Seapsipesus asperus and Sitobion avenae. The t value of Tetragnatha maxillosa, Misumenops tricuspidatus, Neoscona doenilzi, Erigonidium graminicola, Carabus lafossei coelestis and Theridion octomaculatum were 1.4393, 0.1523, 0.1155, 0.8546, 0.7450 and 3.6077, respectively. Therefore, the number of Theridion octomaculatum showed a significant difference (t_0.01=2.82), while the others had no significant differences（t_0.05=2.07）between the two lawns. The comprehensive study on the relationship in quantity and occurrence time