Abstract Insect seed predation and its relationships with seed rain of Quercus aliena were investigated in Tianchi Mountain National Forest Park of Funiu Mountain in Luoyang, a warm temperate forest, from August to September in 2008 and 2009. The results indicated that the duration of seed rain of Q. aliena lasted from middle August to late September. The seed amount at the peak acounted for 78.13% and 75.91% of all seeds in 2008 and 2009, respectively. The seed rain density of Q. aliena was 31.75±16.65 and 51.92±29.26 nuts/m2 in 2008 and 2009, respectively. Seed size in 2009 (1.94±0.61 cm3) was significantly smaller than that in 2008 (2.46±0.57 cm3）. The proportion of intact seeds in 2008 and 2009 was 59.05% and 36.12% respectively, and the proportion of the insect-infested seeds was increased significantly in 2009. We also found that the number of weevil eggs and larvae in each insect-infested acorn was significantly correlated with acorn size, and the infested acorns （2.29±0.42 cm3 in size） were much larger than the sound ones （1.59±0.32 cm3 in size）, indicating the preference of weevils to larger acorns for oviposition. The results suggest that weevils prefer larger acorns for oviposition, and the higher proportion of weevil-infested acorns may be one of the main causes of decline in seedling establishment of Q. aliena.