An acccess control method has been previously performed only focused on safety, and thus not much effort has been done consider access control in terms of efficiency. in this paper, we proposed a method for an efficient and secure query processing of XML data streams, such as a personal digital assistand and portable terminal, at the client side with limited resources. specifically, we proposed in access control processing that possesses a small overhead for attaining a secure result in a limited memory and a method to enhance the performance, finding the parts capable of optimizing each processing step for offsetting the overhead caused by the addition of access control processing. our new method is analyzed through an experiments.