A gas burner for a cooking appliance is a gas burner including a head, an injector holder, a Venturi tube, and an injector, wherein a pair of first Venturi tubes each directly communicate with one of expansion chambers separately formed in the injector holder, each of the expansion chambers communicates with an outer annular chamber through an upright vertical channel thereof, an upper surface of the injector holder is flat, and a second injector is positioned higher than the upper surface of the injector holder and is open.

The present disclosure discloses an energy-efficient upside-entrainment burning system, which includes: a gas distributor component, an ejection pipe component, an outer-ring burner cap, an inner-ring burner cap, a plurality of gas nozzles. The ejection pipe component is arranged below gas distributor component, is provided with two ejection channels in a centrosymmetric structure corresponding to the outer-ring gas mixing chamber, also provided with two ejection channels in a centrosymmetric structure corresponding to inner-ring gas mixing chamber. Each ejection channel is arranged in a Venturi pipe structure. In a gas flowing direction, an ejection pipe inlet, a contraction section, a throat section, an expansion section, an ejection pipe outlet are arranged in sequence. An ejection capability is taken as a target parameter, each ejection capability parameter is of adjustment simulation to obtain optimum design of each structural detail of burner to form the energy-efficient upside-entrainment burning system with an optimum ejection capability.