The invention discloses a method for measuring the liquid level of multiple points with one pressure sensor. One pressure sensor is connected with a plurality of liquid surfaces, wherein the height of one liquid surface is unchanged to serve as a standard liquid surface. All the liquid surfaces are isolated through electromagnetic valves. When in measurement, the electromagnetic valves are respectively opened, so that pressure values under different liquid surfaces are measured. Afterwards, the pressure value of the standard liquid surface is respectively subtracted from all the pressure values, and then the height values of all the liquid surfaces are worked out.