The invention relates to a method for measuring large linearity measuring range data fusion by means of compound color super resolution differential confocal measurement, belonging to the ultraprecise three-dimensional microstructure surface measuring field; firstly, formula 1 and formula 2 are utilized to respectively calculate output information of a first and a second super resolution differential confocal measuring branches, wherein, formula 3 is the actual output light intensity information of a first and a second measuring branches which are respectively obtained by adopting a compound colour super resolution differential confocal measuring device, (the formula 1, the formula 2 and the formula 3 are shown at the upper right side); Gamma1 and Gamma2 are intercepted to obtain effective output Gamma1 and Gamma2, and finally a systemic linear output fusion function (see the formula 4) is constructed and is output as the systemic final displacement response, wherein, GammaB' is a shift factor, lambda1and lambda2 are the wavelength of the first and the second measuring branches. The method remains the advantages of high space resolution and inhibiting common mode additive noise and linear range extension of the compound colour super resolution differential confocal measuring, can inhibit interference of multiplicative noise, and can obtain output characteristic curve with better linearity and larger linear measurement range.