An object identification method of touch system is disclosed. The object identification method includes: repeating an object measurement to obtain a plurality of object signals; conducting a liquid measurement to obtain a liquid signal; determining whether the value of the liquid signal is greater than a first default value or less than a second default value, wherein the first default value is larger than the second default value; proceeding with an elimination step if the value of the liquid signal is greater than the first default value; and, proceeding with a start step if the value of the liquid signal is less than the second default value.