Spider mites are a group of most important pests in tropical agroecosystems. Over-reliance on chemical acaricides has led to severe resistance and residue problems. Neoseiulus longispinosus, a native phytoseiid mite widely distributed in tropical China, is considered a promising natural enemy. However, its quantitative biocontrol capacity and genomic background remain poorly understood. This study aimed to systematically evaluate the application potential of N. longispinosus and to establish its chromosomal-level genomic resources. The predatory mites were fed with both important spider mites on rubber tree, Eotetranychus sexmaculatus, and on vegetables, T. cinnabarinus, respectively. Two-sex life tables were constructed at six constant temperatures (15, 18, 21, 24, 27 and 30 °C). Predation efficacy across temperatures and prey stages was evaluated using the functional response model. Also, Predation trials using T. cinnabarinus reared on potted soybean were conducted at predator-to-prey release ratios of 1:5, 1:10, and 1:20 1:40. The safety of six common acaricides was assessed via bioassays, and toxicity selectivity ratios were calculated. Additionally, a chromosome-level genome was assembled using PacBio HiFi and Hi-C sequencing. Population growth of N. longispinosus was optimal at 27–30 °C, with the highest intrinsic rate of increase reaching 0.34 d-1 on T. cinnabarinusand 0.30 d-1 on E. sexmaculatus. Predation capacity increased with temperature and prey density, but was substantially weakened at 15 °C. Adult N. longispinosus preferentially consumed larvae of spider mites over other stages. Functional responses fitted to the Holling-II model, with peak predation efficiency observed at 24–30 °C. In potted trials, control efficacy of N. longispinosus achieved over 90 % within 18 days, when the release ratios were 1:5, 1:10 and 1:20. Bifenazate and matrine showed high positive selectivity toward both spider mites and N. longispinosus (TSR = 8.3248 and 2.6152, respectively). Genomic analysis yielded a high-quality 199.21 Mb assembly anchored to four pseudo-chromosomes, encoding 12,890 protein-coding genes with high BUSCO completeness. These integrated ecological and genomic findings demonstrate that N. longispinosus is an effective native biocontrol agent for tropical spider mites and provide a foundational platform for understanding its thermal adaptation.