The microscope objective is the key component of the nano-laser direct writing processing system, and the development trend in industry involves a large object-side field of view under a large numerical aperture (NA) and adapting to the change of the refractive index of the photoresist for two-photon polymerization (TPP). This paper compares the indicators of the microscope objective used in current TPP effect research, excavates the relationship between the object-side field of view, NA, and number of lenses, and proposes the objective synthetic sensitivity index (I_ss). Combined with the I_ss, a microscope objective with a wavelength range of 500-800 nm, NA>1.3, and an object-side field of view of 1.0 mm is designed. The resultant design of the objective lens involves a modulation transfer function curve close to the diffraction limit and a root mean square of wave aberration less than 0.07λ and uses the internal focusing method to adapt to the change of photoresist refraction for TPP. Tolerance analysis demonstrates that the design results are feasible.