Base assembly and child safety seat

A base assembly, comprising:

• a base;
• a sliding element telescopically arranged on the base,
• a supporting leg pivotably connected to the sliding element and extended and retracted along with the sliding element, the supporting leg having an unfolded position when in use and a folded position when not in use;
• and
• a supporting leg retractable structure actuating the sliding element and the supporting leg to move toward an inside of the base in response to pivoting the supporting leg from the unfolded position to the folded,
• wherein the base comprises a base bracket, the sliding element comprises a sliding bracket, the sliding bracket is sleeved on the base bracket and is able to slide a certain distance with respect to the base bracket, so that the sliding element is capable of being extended out of the base and at least partially retracted into the base, and
• wherein the supporting leg retractable structure comprises a driving element and a guide assembly, the driving element is arranged inside the sliding element and pivots together with the supporting leg, and the guide assembly converts pivoting of the driving element into an actuating force that moves the sliding element and the supporting leg together toward the inside of the base.