Nucleation was the basis of the fabrication of two-dimensional materials in the bottom-up deposition methods. However, classical nucleation theory (CNT) was not suitable for the nucleation in supercritical fluid (SCF) because of the non-ideality of SCF. Herein, a dilute solution system composed of nonvolatile solute and supercritical carbon dioxide (scCO2) was established and the theory of pressure-induced supercritical phase nucleation (PI-SCPN) was proposed. A new defined solute-solvent correlation function was found to influence the nucleation driving force a lot in this particular process, especially when the supersaturation was small. Furthermore, the corresponding experiments were conducted by using MoO2(acac)2 as solute in scCO2 to verify PI-SCPN. The solubility of MoO2(acac)2 was accurately measured by static equilibrium method. The influence of supersaturation, temperature and pressure on the nucleation were found to be consistent with that predicted using the PI-SCPN. The nucleation rates were compared to the experimental values, showing good agreement.