According to the complicated and various functions of products, the hesitation and product knowledge may influence the result of post-purchase evaluation. But there is less previous research making discussion on the direct effect from hesitation and product knowledge to post-purchase satisfaction. Thus this paper focuses on exploring the impact of product knowledge, hesitation to satisfaction and the influence of satisfaction on regret. This study conducts experiment method to demonstrate the information of product, manipulate the regret(high/low) from word of mouth and then measure these observation variables. The results show that the higher product knowledge cases higher satisfaction and the higher hesitation lead to higher satisfaction. If the customer feels more satisfied then he will fell less regret. Finally, in order to increase customer satisfaction of post-purchase, the marketing manager can provide sufficient product information for the customer to increase product knowledge and decrease the hesitation.