The framing converter is an important two-dimensional spatial resolution diagnostic device in the inertial confinement fusion experiment. In order to study the imaging performance of pulse-dilation framing converter using short magnetic focusing, the spatial resolution and imaging surface are simulated by the electron motion trajectory and imaging distribution of the converter, and the aberration theory is used for analysis. The result shows that the spherical aberration and field curvature of short magnetic focused system are the main reasons for the loss of spatial resolution, the spherical aberration of the single/double lenses tube are 0.229 and 0.07, the field curvature are 0.021 and 0.009, respectively. The smaller spherical aberration and field curvature are, the better imaging performance of the tube is.