The invention discloses a method for computer assisted design of a tobacco group formula by a near infrared spectrum technology. The invention is characterized in that the method comprises the following steps: a near infrared spectrum analyzer scans to obtain the near infrared diffuse reflection spectrum of raw material tobacco; the near infrared spectrum data of inventory tobacco is obtained; relevant information of each tobacco is input, and a database is built; the main ingredients of the near infrared spectrum data of the tobacco are analyzed; the genetic algorithm serves as an algorithmic model to carry out formula fitting operation; and the adjustment of an evaluation function is utilized to obtain a plurality of fitting formulas. The invention can conveniently and quickly obtain the plurality of the fitting formulas, the original adaptive value of the formulas, the number of the tobaccos used for the formulas, formula appraisal, main chemical ingredient content and error.