An apparatus for measuring load weight comprjsing: a lift cylinder; a pressure sensor mounted in the line of the lift cylinder and configured to measure an internal pressure of the lift cylinder; a temperature sensor mounted in the lift cylinder and configured to sense a temperature of an oil in the lift cylinder; and a control unit configured to perform the following steps: storing a plurality of value pairs in the apparatus, wherein each of the value pairs comprises a temperature and a compensate pressure value corresponding to the temperature; determining whether a compensate pressure value corresponding to the sensed temperature is stored in the apparatus, acquiring, if a compensate pressure value corresponding to the sensed temperature is stored in the apparatus, a compensated pressure according to the compensate pressure value stored in the apparatus corresponding to the sensed temperature and the sensed internal pressure; acquiring, if a compensate pressure value corresponding to the sensed temperature is not stored in the apparatus, a first compensate pressure value stored in the apparatus corresponding to a first temperature greater than the sensed temperature, a second compensate pressure value stored in the apparatus corresponding to a second temperature less than the sensed temperature, a compensate pressure value corresponding to the sensed temperature using the first compensate pressure value and the second compensate pressure value, and a compensated pressure according to the sensed internal pressure and the compensate pressure value acquired from the first and the second compensate pressure values. a lift cylinder; a pressure sensor mounted in the line of the lift cylinder and configured to measure an internal pressure of the lift cylinder; a temperature sensor mounted in the lift cylinder and configured to sense a temperature of an oil in the lift cylinder; and a control unit configured to perform the following steps: storing a plurality of value pairs in the apparatus, wherein each of the value pairs comprises a temperature and a compensate pressure value corresponding to the temperature; determining whether a compensate pressure value corresponding to the sensed temperature is stored in the apparatus, acquiring, if a compensate pressure value corresponding to the sensed temperature is stored in the apparatus, a compensated pressure according to the compensate pressure value stored in the apparatus corresponding to the sensed temperature and the sensed internal pressure; acquiring, if a compensate pressure value corresponding to the sensed temperature is not stored in the apparatus, a first compensate pressure value stored in the apparatus corresponding to a first temperature greater than the sensed temperature, a second compensate pressure value stored in the apparatus corresponding to a second temperature less than the sensed temperature, a compensate pressure value corresponding to the sensed temperature using the first compensate pressure value and the second compensate pressure value, and a compensated pressure according to the sensed internal pressure and the compensate pressure value acquired from the first and the second compensate pressure values. storing a plurality of value pairs in the apparatus, wherein each of the value pairs comprises a temperature and a compensate pressure value corresponding to the temperature; determining whether a compensate pressure value corresponding to the sensed temperature is stored in the apparatus, acquiring, if a compensate pressure value corresponding to the sensed temperature is stored in the apparatus, a compensated pressure according to the compensate pressure value stored in the apparatus corresponding to the sensed temperature and the sensed internal pressure; acquiring, if a compensate pressure value corresponding to the sensed temperature is not stored in the apparatus, a first compensate pressure value stored in the apparatus corresponding to a first temperature greater than the sensed temperature, a second compensate pressure value stored in the apparatus corresponding to a second temperature less than the sensed temperature, a compensate pressure value corresponding to the sensed temperature using the first compensate pressure value and the second compensate pressure value, and a compensated pressure according to the sensed internal pressure and the compensate pressure value acquired from the first and the second compensate pressure values.