The paper presents a parallel algorithm framework to answer shortest distance queries on dynamic graphs. Based on maintaining a delta graph, multiple queries within a batch are executed in parallel over different versions of data graph by multi-threading. For each query, bidirectional breath-first search (BFS) is utilized to reduce search space. During the search process, an exploration direction decision-making function is proposed. Furthermore, adjacency-lists of data graph are encoded by BSR layout, combined with SIMD instructions and graph reordering algorithm, higher degree of data-level parallelism is achieved. Extensive experiments on real graph datasets confirm the superior efficiency of the proposed solution.