Abstract: Pitch marking plays a key role in speech synthesis and other areas. The pitch marking algorithm based on dynamic programming, which is commonly used at present, has some shortages. For instance, its constraint criterions are usually too simple, and the dynamic programming method it adopts considers local optimum heavily but global optimum. On account of this, a new method of pitch marking based on beam search algorithm is proposed. Except pitch period and amplitude, figure and index position are brought in the constraint criterions to select the candidates more restrictedly. Further more, beam search algorithm is employed to extract the pitch marks, for basic consideration of the global optimum and giving due consideration to the local optimum. Besides, a pitch contour extraction method based on beam search algorithm is proposed, which extracts the pitch contour from the outputs of several pitch detection algorithms, to obtain more accurate pitch marking result by improving the precision of pitch period estimation. Simulation results indicate that, compared to the traditional pitch marking algorithm based on dynamic programming, the new method of pitch marking based on beam search algorithm owns higher accuracy rate. In the simulation test, the average accuracy rate of the new method is 98.57%, while the average accuracy rate of the traditional algorithm is 94.70%.