Concerning the inability to make full use of existing business resources in the current software project development process, which leads to low development efficiency and weak capabilities, a cognitive graph based on software development process was proposed by studying the interrelations among business resources. First, a method for building knowledge hierarchy by extracting business knowledge from formal documents was developed and corrected. Second, a network representation model for software codes was constructed through code feature extraction and code entity similarity investigation. Finally, the model was tested using real business data and was compared with three other methods: Vector Space Model (VSM), diverse ranking method and deep learning. Experimental results show that the established cognitive graph method based on business process is superior to current text matching and deep learning algorithms in code retrieval; the cognitive graph method improves precision@5, mean Average Precision (mAP) and Normalized Discounted Cumulative Gain (?-NDCG) by 4.30, 0.38 and 2.74 percentage points respectively compared with ranking-based code search effectively method, solving many problems such as potential business vocabulary identification and business cognitive reasoning representation, and improving the code retrieval effect and business resource utilization.