Thermoregulated phase-transfer Pd nanocatalyst was firstly employed in the selective hydrogenation of 1,5-cyclooctadiene (1,5-COD) at atmospheric hydrogen pressure. Under the optimal conditions, > 99% conversion and 95% selectivity to cyclooctene (COE) were obtained. The Pd nanocatalyst can be easily separated from products and directly reused. The turnover frequency (TOF) of 1411 h(-1) is the highest value ever reported among Pd nanocatalysts at atmospheric hydrogen pressure.