In recent years, astronomical observation has put forward higher requirements for observation environment, resolution power and simultaneous observation quantity, which makes the cost of traditional spectrometer spiraling. The development of  integrated  photonics  provides  a  miniaturized,  low-cost  and  environment-friendly  solution  for  astronomical  spectral observation. However, high resolution spectrum is hard to achieve because of the highly repetitive structure and defocus aberration existing in re-imaging system when needing cross dispersion. Based on Silica-on-Silicon material platform with a refractive index contrast of 0.23%, new structure of cascaded modulation arrayed waveguides(CMAW) with total length difference  of  22mm  are  arranged  in  a  square  chip  with  a  side  length  of  40mm,  having  a  theoretical  resolution  of  20,000@1550nm and tested resolution of 15,000@1550nm. Our work demonstrates the potential of integrated photonics applying in high resolution astronomical spectral observation, three times above the record of available resolution power international, which is expected to provide a solution for space observation and large-scale spectral survey.