With limited area meso-scale numerical model under η-coordinate,sensitivity experiments of retrieving model humidity profiles by one-dimensional variational assimilation of digital weather radar-derived precipitation are studied for the abrupt heavy rainfall along the Yangtze River in the east part of Hubei Province. Results show as follows. Different initial values X⁽⁰⁾of humidity profiles have great effects on the decline of the object function, and different initial evaluation schemes of humidity profiles have substantial effects on the results of rainfall variational assimilation under the special condition that model background precipitation equals to zero while observation precipitation does not equal to zero.