To find the cognitive principle through a cognitive model,a cognitive model based on single unit event is designed.The cognitive object of the model is cognition.The cognitive structure of the model consists of sensing part,accepting part,storing part,problem-solving part,thinking part and reasoning part.In the same testing cognitive process,the simulation of cognitive process is tested,when the capacity of the memory bank is given different values,the changes of the cognition stored in memory bank are recorded,and the cognitive data are calculated.The results show that the cognitive model is able to simulate cognitive process.As the cognitive process goes on,the cognition dimensions,the cognition quantities,the cognition multiplicities and the location of cognition in the memory bank often alter.All the cognitive data increase when the capacity of the memory bank enlarges and the data are modified when the problems are solved.