Cement grouting has been widely used in underground rock engineering projects for groundwater flow management. Analysis of cement grout propagation in rock fractures is important for the design, execution and monitoring of rock grouting in practice. At present, analysis of rock grouting mainly relies on theoretical models or methods, such as the real time grouting control (RTGC) method. Specifically, in the RTGC method, it is assumed that the cement grout is injected into an idealized fracture consisting of smooth parallel plates or disks with constant injection pressure. In reality, the injection pressure can vary over time, and it is in many cases not necessarily constant during the entire grouting process. In this work, we extend the RTGC method with consideration of varying the injection pressure over time, by assuming that the propagation process of cement grout in rock fractures is under a pseudo steady state. Illustration and application examples for cement grout propagation in fractures with varying injection pressures are analyzed by using this extended method. The results generally show that the extended method can predict the propagation of cement grout in fractures and the evolution of injection flowrate with varying injection pressures in typical rock grouting applications. Therefore, the extended method can be readily used for the theoretical analysis of rock grouting in practice.