In order to analyze the learners＇ cognitive process under the teacher＇s focus-on-form feedback on second language writing, this study carried out an simulation experiment to investigate learners＇ correction rates and confidence levels according to three major variables： feedback modes, error types and treatment orders. The results show that： （1） treatments of ＂Code＂ and ＂Underline＂ both had their advantages and disadvantages under different situations; （2） different types of errors are sensitive to different feedback modes; （3） orders of treatment may influence learners＇ perception of instructor＇s intention; and （4） learners＇ confidence level may record the cognitive level of the target language and correlate with the correct rate. Finally, it is suggested to pay more attention to the interactive mechanism of feedback effect and to apply more diversified treatments under various situations in practice.
