The invention provides a forklift imbalance alarming device and method. The forklift imbalance alarming device comprises a weighing sensor, a main processor and an alarming device body. The forklift imbalance alarming device is characterized in that the weighing sensor is used for measuring pressure generated by a left fork and a right fork when a forklift is loaded and transmitting the measurement result to the main processor; the main processor judges whether the forklift overloads or is imbalanced and outputs the condition to the alarming device body to remind operators when the forklift overloads or is imbalanced; the alarming device body is used for receiving and displaying the signal about the forklift overload or imbalance condition transmitted by the main processor. The forklift imbalance alarming device and method can calculate various overload and imbalance conditions possibly occurring to the forklift, feed the conditions back to the operators by many means in time, and ensure operation safety of the forklift.