White light interferometry is employed to research on the measurement technology for large scale evaluation and a dedicated system is developed on the platform of nano-measuring maching (NMM). Firstly, this work calibrates the environment effects and the results are given quantitatively. Secondly, under the condition of the precise environment control, the non- overlapping stitching method is investigated, and the comparison of the results is also made; For non- periodic array aspheric optical surface, white light tilted scanning interferometry is employed to perform the large range measurement. During the scan, the specimen moves through the coherence area along a sloping direction, and the objective field of view limitation is removed. ence, within one round of scan, the surface in millimetre scale can be successfully evaluated. For the scanning process, this article analyzes the interferogram slipping out and the impact due to the difference of the two angles appeared in this technology. Finally, the comparison between the above two methods is given.