The present disclosure provides an induction coil assembly and a reaction chamber. The induction coil assembly includes an induction coil arranged over a dielectric window of the reaction chamber. Two ends of the induction coil include a power input end and a ground end, respectively. A vertical spacing between the two ends of the induction coil and the dielectric window is greater than a vertical spacing between a portion between the two ends of the induction coil and the dielectric window. The induction coil and the reaction chamber provided by the present disclosure may reduce the capacitive coupling of the two ends of the induction coil by ensuring that the coupling strength of an RF magnetic field satisfies the requirement to reduce sputtering on the dielectric window and improve process results.