We have studied the growth and optical properties of AlInGaN alloys in this arti cle. By the measurement of three samples, we found that the incorporation of In decreases with the increase of temperature, while there is nearly no change for the incorporation of Al. The sample grown at the lowest temperature had the best material and optical properties, which owes to the high In component, because t he In component can reduce defects and improve the material quality. We also use d the time_resolved photoluminescence(PL) to study the mechanism of recombinatio n of carriers, and found that the time dependence of PL intensity was not in exp onential decay, but in stretched_exponential decay. Through the study of the cha racter of this decay, we come to the conclusion that the emission comes from the recombination of localized excitons. Once more, this localization exhibites the character of quantum dots, and the stretched_exponential decay results from the hopping of carriers between different localized states. In addition, we have u sed the relation of emission energy dependence of carrier's lifetime and the cha racter of radiative recombination and non_radiative combination to confirm our c onclusion.