The on-orbit object auto-cataloguing of Space Surveillance Phased Array Radar (SSPAR) contains two progresses, one is catalogue improvement, the other one is catalogue maintenance. In the catalogue improvement, SSPAR captures the new on-orbit objects in the search fence, and grows the record count of the catalogue database. In the catalogue maintenance, SSPAR samples the catalogued objects' arcs and updates their stable orbital elements. The auto-cataloguing capacity of SSPAR is highly dependent on the stable tracking and updating rate, which will be influenced by many radar parameters. If SSPAR's total time resource is allocated rationally between the searching task and tracking task according to SSPAR's work parameters and objects' orbital characteristics, SSPAR's auto-cataloguing capacity will be improved remarkably.