Aluminum is the most abundant metal element in the earth’s crust. And is a common metal frequently used in our daily life. However, recently, there are reports that aluminum ions show a toxic effect. It is very bad influences for human body, can cause serious diseases associated with brain damage (such as Alzheimer’s disease, Parkinson’s diseases, etc...). Therefore, the detection of Al3+ is very important. Recently, the reported methods include electrochemical methods and fluorescent analysis. However, these methods require large equipment and costly. Here in we report a method to detect by colorimetric method in which color changes when reacting with aluminum via gold nanoparticles synthesized using apple juice. Especially, gold nanoparticles using apple juice(Ap-AuNPs) are superior in reactivity with aluminum ions when compared with existing bare AuNPs, so it can be said that it is more sensitive. Based on the above research, we expect to be applied to the detection of aluminum ions in real life by conducting experiments in the same way by using real samples (tap water, river etc.).