A method for estimating the vertical wind field from single Doppler radar Range-Height Indicator (RHI) is developed. By using the atmospheric continuous equation and the two-dimensional supposition to real wind, the wind components perpendicular to the axis of the radar beam within the radar vertical scanning plane are calculated. Several experiments show that the method is able to retrieve the vertical section of wind structure in the rain band reasonably, and it can be further applied to the study of Doppler weather radar observations.