Abstract: In order to improve the mixing efficiency of different reactants in microscale, a study on optimization of the structure and working parameters of the Y type pulsing micro mixer is conducted, in which the effects of the structure and parameters on mixing performance are taken into consideration. By simulation analysis, the channel section size, entrance angle, entrance flow rate and pulsation frequency are optimized. Based on the optimized structure and working parameters, a test prototype was made in lab. Using chemical reaction probe method, the prototype is tested. After detecting the size and distribution of gold nanoparticles by controllable synthesis, the mixing performance is evaluated synthetically. The test results indicate that when the entrance flow rate and working frequency are ascertained, there exist corresponding optimum values of the section size and flow rate of the Y type pulsing micro mixer. The entrance flow rate and working frequency are important parameters which influence each other. A certain flow rate corresponds to an optimum mixing frequency.