Abstract:In mountainous seismic exploration, currently we commonly use the first breaks travel time to-mographic approach to invert the velocity structure in relief near surface, but final inverted results are affected by many factors. The paper,through a lot of numeric tests, analyzed and correlated in detail the main factors that have influence on the tomo-graphic inversion precision of near-surface model such as equation solution,prior information usage, geometry,initial model and smoothing factor,sunv marized the selected principle and range of optimum parameters and created interior constrained e-quation. Application of the method presented by the paper to practical data processing achieved better imaging effect.