Abstract: The high fidelity data of low-altitude wind shear is the necessary foundation for flight performance analysis and low-altitude wind shear detection. To solve the difficult problem of real data obtainment, which is caused by the characteristics of suddenness, short duration and high hazard, a three-dimensional modeling method of low-altitude wind shear via function fitting is proposed in this paper. On the basis of hydrodynamic characteristics of wind shear, the three-dimensional density and velocity field is simulated by using the function fitting method. Then, according to the scanning process of airborne weather radar, which is under the wind shear detection mode, the radar echo simulation of the low-altitude wind shear is realized. Results of simulation have proved that the method can realize the three-dimensional wind field modeling of low-altitude wind shear flexibly and quickly. The wind speed estimation of echo signals can indicates the relationship between the Doppler velocity and distance which has the distribution characteristics of “S” shape.