A determination method of trace Ni(II) and Zn(II) in aqueous solution was studied and developed by adsorbing on titanium dioxide. For this purpose, several conditions were optimized such as the pH of sample solution, adsorption time, the types and concentration acid, and desorption time. The titanium dioxide was added in sample solution which was pH adjusted. Then, the sample solution was stirred for 5 minutes. This mixture was stored in room temperature for 30 minutes to allow adsorption. After filtering and washing the titanium dioxide, the analytes were dissolved from the titanium dioxide on membrane filter by an ultrasonic vibration for 10 minutes in 1.0 M $HNO_3$ solution. Then, this sample solution was analysed using ICP-AES. The adsorption equilibrium was achieved in 30 minutes. The desorption was the most of effective with 1.0 M(mol/l) nitric acid solution, and desorption time was 10 minutes. This procedure was applied for the analysis of two real samples, i.e., brown seaweed and tangle. The recoveries of Ni(II) and Zn(II) in spiked samples were 89.4${sim}$98.9% for analytes.