Abstract: For ignition and high fusion gain, it’s the key issue to achieve high implosion velocity in inertial confinement fusion. The important implosion dynamics quantities like implosion velocity and residual mass can be diagnosed by implosion ablated convergence measurement. The measured results will be used to modify the point design, optimizing the ablator materials, thickness and laser pulse profiles. In recent years, we demonstrated the conventional implosion ablated convergence measurement on Shenguang laser facilities with the slit imaging technique. The high spatial resolution monochromatic imaging technique based on the spherically bent crystal was developed and used for the implosion ablated convergence measurement. With the continuing improvements of the imaging system and the modification of the diagnostics, a high spatial resolution implosion trajectory diagnosis has been implemented. The implosion velocities are measured with high precision while the uncertainties are not greater than 2.1%.