The invention discloses a method for calculating the overall roughness of the two-dimensional contour surface of a particle. The method for calculating the overall roughness of the two-dimensional contour surface of the particle comprises the steps that S10, the edge of the particle is zoned, each zoned area is scanned, the scanned pictures of the zoned areas are obtained, the scanned pictures ofthe zoned areas are spliced to form a complete contour picture, every two adjacent zoned areas have an intersection area, and the actual contour of the particle is showed on the complete contour picture; S20, the Fourier function is constructed based on the actual contour, and the Fourier coefficients and reference coordinate points are calculated, and the reference contour is constructed based onthe reference coordinate points; and the S30, the contour surface roughness of the particle is calculated based on the reference contour and the actual contour. The technical problems that for irregular two-dimensional particles, most roughness calculation methods are not applicable, the calculation is not scientific, and the accuracy is low are solved.