Frequency combs are useful in a wide range of applications,such as optical metrology and high-precision spec-troscopy.We experimentally study a controllable frequency comb generated in a tunable superconducting coplanar-waveguide resonator in the microwave regime.A two-tone drive is applied on one of the resonance modes of the resonator and comb generation is observed around the resonance frequency of the resonator.Both central frequency and teeth density of the comb are precisely controllable,and the teeth spacing can be adjusted from Hz to MHz.Moreover,we show that a few hundreds of sidebands can be generated using a sufficiently strong drive power and the weakest drive power needed to generate the comb can be reduced to approach the quantum limit.These experimental results can be qualitatively explained via theoretical analysis.