•A collision dependent nucleation model was developed by simulating silver nucleation at different collision conditions.•The model was evaluated by simulating silver particles aggregation.•The model was validated by silver crystallization experiments conducted in an in-situ electron microscopy.•The model was applied to the improved synthesis of silver catalysts for ethylene epoxidation. Nucleation is widely present in nature, from food production to haze generation. Owe to the spatiotemporal limitation in catching the dynamic characters of nucleation process, the theoretical development and the control technique of nucleation is far behind the demand. Here we report a strategy of controlling nucleation process via manipulating the collision of nucleation units, with the aim of disclosing the mechanism dominating the nucleation process. Silver nucleation is simulated at different collision conditions which is regulated by chemicals diffusion and reaction rate. It is found that the nucleation rate has a good linear relationship with the collision frequency, suggesting a collision dependent nucleation model. This model is evaluated by particles-based silver aggregation and validated by experiments conducted in an in-situ electron microscopy. Furthermore, the model is applied to the improved synthesis of silver catalysts for selective partial oxidation of ethylene.