A phase shifter and a liquid crystal antenna are provided. The phase shifter includes a first substrate and a second substrate opposite to each other, and a liquid crystal layer between the first substrate and the second substrate. The first substrate includes a first base plate and a first electrode at a side of the first base plate proximal to the liquid crystal layer. The second substrate includes a second base plate and a second electrode at a side of the second base plate proximal to the liquid crystal layer. The phase shifter further includes an auxiliary capacitor connected to the first electrode.