Forced ignition of kerosene spray with hot gas injection was investigated experimentally in an expanding scramjet combustor with incoming air total temperature of 800K and Mach number 2 which was related to a typical cold start-up condition of dual-model scramjet.The fuel was injected vertically into the crossflow upstream the flame-holding cavity.The kerosene spray shadow and self-luminosity flame evolvement during the process of ignition were observed using high speed camera.The effects of injection scheme such as position and direction of hot jet on the ignition results and cavity-trapped flame generation were compared and analyzed.Results reveal that the enhanced ignition by hot gas injection is characterized by the far-field diffusive burning between spray and hot jet.The trapped flame within cavity is created due to the flame propagation upstream which is the dominant mechanism of successful flame establishment.