An image-encoding method and apparatus is provided for using a table statistically reflecting a selection frequency of a quantization parameter. The method includes the steps of preparing a table representing a relationship among a target bit quantity, a quantization parameter and a selection frequency as a table for statistically reflecting a frequency of selecting a quantization parameter according to a target bit quantity. The method further includes the steps of searching for a maximum selection frequency among the selection frequencies corresponding to an input target bit quantity by referring to the table, and selecting a quantization parameter corresponding to the input target bit quantity and the searched maximum selection frequency as an optimized quantization parameter to thereby prevent inadequate image-encoding due to large amounts of computations and provide a target bit rate and uniform image quality.