Abstract: A finite difference method is adapted to simulate liquid metal flow in delivery tube of spray forming. Numerical calculations of minimum superheat, (which is needed to avoid delivery tube blockade due to metal premature solidification), are conducted for different liquid metals (Fe, Zn, Al), and process parameters. A semi-quantitative correlation is derived. Based on the calculated results, for the minimum superheat, the heat conductivity of delivery tube is the most imortant factor, a inapppropriate selection of tube materials will cause superheat beyond permission; increasing overpressure also can decrease minimum superheat significantly; the other critical factor is the design of delivery tube configuration, reducing the length/diameter ratio (L/D) can decrease minimum superheate, specially for metals with high melting point or delivery tube with high thermal conductivity.