With the rapid development of aerospace, the requirements for liquid hydrocarbon fuels with the high energy density are increasing. The energy density of traditional hydrocarbon fuels is low, which cannot meet the application requirements. Aluminum powder has a high energy density. The addition of nano-aluminum powder to hydrocarbon fuels can increase the energy density and improve the ignition and combustion characteristics. To determine the effect of the change of nano-aluminum powder from low concentration to high concentration on the ignition and combustion characteristics of liquid hydrocarbon fuels, the ignition and combustion characteristics of aluminum/ethanol based nanoslurry fuel droplets with different concentrations (2.5wt%, 10wt%, 15wt%, and 20wt%) of nano-aluminum powder were studied by a droplet hanging method. The whole combustion process of the droplet was captured by a high speed photography system. The ignition delay time, the ignition temperature, and the droplet life were analyzed by a temperature acquisition system and an image collection system. The results showed that the temperature and the concentration of nano-aluminum powder had great influence on the droplet combustion characteristics. The ignition delay time and ignition temperature of the ethanol droplet can be reduced by adding nano-aluminum powder, and the droplet life can be shortened. Especially, the ethanol droplet with 2.5wt% nano-aluminum powder had the shortest ignition delay time. The ignition delay time and droplet life of sample S2, ignition temperature of sample S3, can be decreased by 42.20%, 18.43%, and 28.57% contrast to sample S1 at 750℃, respectively. With the increase of temperature, the ignition delay time and the ignition temperature of ethanol and aluminum/ethanol nanoslurry fuel droplets were significantly reduced. When the temperature was higher than 750℃, their decrease amplitude decreased. The concentration of nano-aluminum powder was closely related to the micro-explosion of droplet. The degree and the duration of the micro-explosion of droplet increased with the increase of nano-aluminum powder concentration, while this trend became stable when the concentration of nano-aluminum powder exceeded 10wt%. It was proved that the concentration of nano-aluminum powder and the ambient temperature were both important factors to affect the combustion characteristics of the aluminum/ethanol nanoslurry fuel droplet.