It is difficult to retain plug in conventional consolidation plugging. To improve the slurry residence, the two-stage consolidation plugging is often used in the field. Namely, a high viscous slurry is injected into leakage layer before consolidation plugging slurry. In the process of plugging, the law of wellbore pressure change is not clear, the wellbore pressure cannot be finely controlled, and the determination of parameters such as displacement and slurry volume lacks theoretical guidance. These remain one of the key issues facing the optimization of the consolidation plugging process. Based on the one-dimensional radial flow model of slurry in cracks, a dynamic model of two-stage consolidation plugging was built. Two evaluation parameters for the retention of plugging slurry in cracks, the critical pressure and pressure difference ratio were proposed. Taking the two-stage consolidation plugging of high viscous gel slurry + cement slurry as an example, the influence of fracture width, slurry displacement, slurry volume and proportion on wellbore pressure was analyzed. The relationship between the change of annular liquid level height and wellbore pressure during plugging was clarified. The results indicate that the smaller the fracture width is, the greater the wellbore and formation pressure difference and critical pressure difference are, and the better the slurry retention in the fracture is. Increasing the slurry volume and high viscous slurry proportion helps the slurry to reside, but multiple factors such as slurry residence, crack sealing and the cost should be considered. The larger the slurry displacement, the greater the differential pressure ratio, which is not conducive to slurry residence. The change of wellbore pressure can be judged by the change of annular liquid level height, and the monitoring of annular liquid level height should be strengthened in the field.