<p>The Lie group analysis is highly effective in solving nonlinear physics or engineering problems. This paper applies the Lie group algorithm to the computational acoustics problem to analytically analyse the transmission characteristics of the spatial sound field information radiated by a steady-state sound source. Firstly, in terms of modelling sound intensity radiation, this paper establishes a nonlinear control equation system for the potential energy of sound density function and sound pressure phase function based on the variational method in the Lagrange mechanical system. Secondly, modern Lie group analysis method is introduced to obtain the Lie symmetry-determining equations of the sound field partial differential equations and the characteristics of the generator functions. Finally, using the relationship between the Lie symmetry and conserved quantity, the conserved vector form and group-invariant solution of the sound field are derived in detail. The research shows that, in the analytical solution of the sound intensity distribution in steady sound source radiation obtained by Lie group analysis, the sound energy potential energy density function can be a conserved quantity, and the sound pressure phase function can be a positive product of the angular frequency and spatial scale of the sound source, which is consistent with the wave theory of the classical Helmholtz’s equations of the sound field, and the conservation of sound energy density can be used to quantitatively predict the attenuation of steady-state sound pressure levels with propagation distance. Therefore, the Lie group algorithm can provide a reference value for the numerical simulation of sound field wave equation considering various boundaries and initial condition.</p>