On the basis of the introduction of Predicting the 1975 Haicheng Earthquake published on Bulletin of the Seismological Society of America, we further discuss the earthquake prediction event of Haicheng-Yingkou M_s7.3 earthquake in Liaoning which occurred on February 3, 1975, complement and correct the process of some forecast events. Based on the discussion of some points of this article, we focus on the analysis of inevitability and fortuity of the prediction process and result. We make dialectical analysis of the whole prediction process by dividing it into several parts, and believe that in the long-term and short term prediction about Haicheng earthquake, there is more inevitability, while in the impending prediction there is more fortuity, which resides in the inevitability. The prediction about Haicheng earthquake can't be simply attributed to the prediction process of "small earthquakes are active, then strong earthquake come", but a comprehensive view consisting of a series of prediction elements, which still has an inheritable value in the study of Haicheng earthquake prediction.