Current situations of water conservancy development in China include: water shortage and serious water pollution; total water reservoir capacity is large but most are dangerous reservoirs; wide distribution and directly serving the broad masses; business is comprehensive and many fields are involved; projects include public welfare and operating types; great regional difference and problems are varied; utilization methods are extensive and water environment is vulnerable. Based on these situations, this paper analyzes the public goods feature of water resource facilities and management mechanism, and points out that water conservancy development should not merely depend on the market force. Then, it discusses that the influence and trust of transformation period on the whole social members are requirements of new harmonious rural communities, and expounds the necessity of trust for building long-term mechanism for water conservancy development. Finally, it presents policy suggestions: trust is closely connected with benefits of every person, thus developing community trust should begin with every individual; building long-term mechanism for water conservancy development should rely on cultivating highly trust-based rural community shared values.