To define changes in metabolic pathways in response to mandibulate insect feeding and to provide a reference for further investigation of the molecular mechanisms underlying the development of conifer resistance, Chinese pine ( Pinus tabuliformis Carr.) in good growth status in Huangtuliangzi Forest Farm Pingquan city, Chengde city, Hebei Province, was stimulated by 10 pine caterpillars ( Dendrolimus tabulaefomis Tsai et Liu) as feeding stimulation (FS) and leaf clipping control (LCC) as mechanical damage. The metabolome and total flavonoid content were measured in the needles at 0 (with no treatment, CK), 2, and 8 h after treatment. Plant hormones were measured with needles at 0, 0.5, 1, 1.5, 2, 4, 6, and 8 h after different treatments. The plant hormones jasmonic acid (JA) and auxin (IAA) were upregulated within a short time (2 h) after treatment, showing an expression trend consistent with the corresponding substances in the metabolome. A total of 30.8% of flavonoids were identified by metabolomics analysis. Analysis of KEGG metabolic pathways for the different accumulated metabolites (DAMs) showed that the top pathway annotated and enriched for DAMs in comparison to 2 h after FS (marked as 2 h) and 2 h after LCC (marked as LCC 2 h) was flavonoid biosynthesis; the top pathway mainly annotated and enriched for DAMs in comparison to 8 h and LCC 8 h was the same. Thus, the flavonoid pathway is one of the main pathways involved in resistance formation in conifers, and JA and IAA are involved in the development of resistance and growth during biotic stress.