Link prediction and spurious link detection in complex networks have attracted increasing attention from both physical and computer science communities, due to their wide applications in many real systems. Related previous works mainly focus on monopartite networks while these problems in bipartite networks are not yet systematically addressed. Containing two different kinds of nodes, bipartite networks are essentially different from monopartite networks, especially in node similarity calculation: the similarity between nodes of different kinds (called inter-similarity) is not well defined. In this letter, we employ the local diffusion processes to measure the inter-similarity in bipartite networks. We find that the inter-similarity is asymmetric if the diffusion is applied in different directions. Accordingly, we propose a bi-directional hybrid diffusion method which is shown to achieve higher accuracy than the existing diffusion methods in identifying missing and spurious links in bipartite networks.Link prediction and spurious link detection problems are longstanding challenges in network study [1]. They have applications in many fields such as chemistry, biology, sociology and computer science. In many biological networks, such as food webs, proteinprotein interaction networks and metabolic networks, whether a link between two nodes exists must be demonstrated by field or laboratorial experiments, which is usually very costly [2]. In addition, the data in constructing biological and social networks may contain inaccurate information, resulting in spurious links [3]. Correcting the network connections can be very expensive if it is done by laboratorial experiments. To solve this problem, many networkbased methods have been developed and they are shown to have high accuracy in identifying missing and spurious links [4].So far, most related works focus on monopartite networks in which only one type of nodes exists [5]. However, many systems coupled by two different building blocks should be modeled by bipartite networks. For example, the e-commercial systems consisting of online users and items [6], the scientific collaboration system consisting of authors and papers [7], family name inheritance system consisting of babies and names [8] are naturally described by such networks. The link prediction and spurious link detection problems are not yet well addressed in bipartite networks. One close problem is the so-called "network-based * Corresponding authors.