Abstract: A general program using finite-difference method is written to calculate the flow field of supersonic axisymmetric nose inlet. This program is suitable to the direct problem of aerodynamic design of inlets e. g. pitot-type, single-cone, bicone, triple-cone and isentropic cone etc. Since "seperation singularity" difference method and implicit-explicit difference scheme are adopted in the calculation of inviscid flow field in the inlet, results of calculation are obtained with second order accuracy at boundary points and internal points, as well as near singular points. This program can offer required internal and external flow characteristics of inlets.Numerical results for five examples are in satisfactory agreement with corresponding results obtained from the method of characteristics and experimental data.