The effect of ozonolysis activated autoignition on jet flame dynamics is investigated with a non-premixed jet burner numerically and experimentally. High speed camera is used to record chemiluminescence from the autoignited C2H4 jet surrounded by oxidizer consisting of O2/O3/N2. It is observed that the ozonolysis controls the autoignition and can promote the flame stabilization. Firstly, multiple autoignition kernels can be generated and co-exist. They can merge and effectively move the front of the reacting to upstream at a speed of more than 100 times of SL. Secondly, due to ozonolysis reactions, the reactants at the upstream is already reacting prior to the autoignition kernel propagates back. This enhances the propagation by more than 10 times as thermal energy and radicals are not dependent on the relatively slow diffusion process. A simplified model considering the mixing and chemistry timescale is proposed to explain the dependence of location of autoignition kernel on the flow velocity. A reacting 3D FLUENT simulation is conducted with a proposed 5-step mechanism, which predicts the formation and evolution of the autoignition kernel.