A handwriting input recognizing method comprises following steps. Recognize an initial touch point of a touch. Determine an input region associated with the initial touch point. Display the input region. Recognize and display a handwritten input in the input region. Determine whether there is a handwritten input reaches the boundary of the input region. If yes, recognize and display the letters associated with the handwritten input and determine whether the input region receives another handwritten input during a predefined time duration. If yes, determine the sting of letters associated with the handwritten input is a first portion of a complete word, and the sting of letters associated with the another handwritten input is a last portion of the complete word. Combine the first portion and the last portion into a complete word. display letters of the first portion and the last portion in a substantially same size.