Abstract: There are asymmetrical power relations between a questioner and a responder in a criminal court investigation.The questioner controls the responder by asking questions and further controls information.Process control is an important way of control by questions.This article studies the pattern of information flow in process control by presenting a theoretical framework for exploring process control in courtroom question-response, identifying the types of process control and analyzing its inter-sentence development of information.Legal discourse information elements are regarded as the units of information flow.It is found that advancement of Process elements, summary, change and addition of entity elements, replacement of Process by entity as well as flow of environment elements all contribute to increment of discourse information and control of the direction of information flow.It is hoped that this article can serve as a reference for judges, public prosecutors and defenders on questioning strategy and skills for controlling courtroom question-response process.