Spectral synthesis technology is an important technical approach to achieving high-energy laser output. Ensuring high-quality laser output under the premise of high-power output has become the most urgent goal in further developing spectral synthesis technology. Aiming at the challenge of parameter detection for 155 mm × 140 mm rectangular aperture, (1064 ± 3) nm, (1030 ± 3) nm, and (635 ± 5) nm band beams, we design a large-aperture multi-band multi-parameter detection system. The wavefront detection unit is based on Kepler’s telescopic structure, the conjugate relationship between the deformable mirror and the microlens is constructed, at the same time, the compressed beam matches the detector size. The front group objective lenses adopt a Cassegrain structure to solve the problem of color difference correction in large-aperture and multi-band. The rear group of mirrors adopts a three-piece apochromatic refractor group, which compensates for the color difference while accounting for the non-thermal design. It can be used for compensation to the residual thermal difference of the front group of objectives and the thermal difference of the rear group of mirrors. After passing through the wavefront detection unit, the beam quality and beam uniformity can be measured. In order to improve the environmental adaptability of the system, it was designed through an optical passive anthermic method at 20 °C±10 °C. Finally, the system was installed and tested, and the wavefront spot image collected by the wavefront detection camera was restored using the Zernike wavefront restoration method. The measured RMS value of the wavefront of the system is better than 0.0524λ (λ=632.8 nm), the beam uniformity is better than 0.893, and the beam quality β factor is better than 1.26 times the diffraction limit at 10 °C-30 °C.