Based on the principle of symmetry, this paper extends the general relativity’s description of space’s curvature and expansion to the conclusion that space has density. On this basis, the relation between the increment of spatial density and the spectral redshift of light propagating in space is deduced according to the conservation relation of space-time in special relativity. In addition, according to the description of the space structure of gravitational mass and charge in the material space theory. The increased space due to the existence of charge is calculated, and the relationship between the linear density of protons and the spectral redshift on the observation path is deduced. Finally, the relationship between the spectral redshift due to spatial density and the regression velocity of the galaxy is obtained： . Through calculation, the Hubble constant generated by the space density is (114.02793Km/s) /Mpc, which is basically consistent with the observed results. The results show that the observed acceleration expansion of the universe is an illusion caused by the spectral redshift due to the space density of the universe. The universe is not accelerating expansion.
Keywords: Hubble constant, accelerated expansion, space density, spectral redshift, universe
