The indium and aluminum droplets were simultaneously grown on GaAs (001) substrate by droplet epitaxy method. The morphology of the samples with different indium and aluminum components was characterized by atomic force microscopy (AFM), and the distribution of elements on the surface was observed by XPS and scanning electron microscope (SEM). Results show that the density of InAlAs nanostructures on the surface of mixed deposition decreases with the decreases of indium composition, while the size of individual nanostructures increases. The experimental results show that the density of surface InAlAs nanostructures after hybrid deposition decreases with indium component decreasing, while the size of individual nanostructures becomes larger. SEM and XPS test results prove that the indium on the surface is not all segregated due to the high substrate temperature. It is speculated from the experimental results that when indium & aluminum droplets are deposited on the surface, a mixed indium & aluminum droplet is formed. The formation of dips in the center of the nanostructures formed after complete crystallization of the droplets is mainly due to the downward etching of droplets.