For cylindrical conformal array, the performance defects of applying Multiple Signal Classification(MUSIC) algorithm with shading effect are analyzed from the aspect of subspace. A method of biased MUSIC is proposed to solve the shading problem while keeping as high performance as classical MUSIC algorithm by subtracting a constant from the denominator of classical MUSIC spectrum expression. Then a fast Direction of Arrival(DOA) estimation method is proposed by using MUSIC with data-adaptive sub-array divided cylindrical array. This method applies sparsely sampled classical MUSIC algorithm to pre-estimate signal DOA; and then determines sub-arrays and searching sectors according to estimation results; finally estimates signal DOA using classical MUSIC algorithm which only operates in search sectors with signals received from sub-arrays determined previously. This method settles the problem of high computational complexity and low precision for DOA estimation using MUSIC with conformal array confronte with shading effect. Simulation results indicate this method can reduce computational complexity, and meanwhile improve DOA estimation precision.